diff --git a/doc/ca65.sgml b/doc/ca65.sgml
index 19fd3aa2a..da094359c 100644
--- a/doc/ca65.sgml
+++ b/doc/ca65.sgml
@@ -125,6 +125,7 @@ Long options:
   --target sys                  Set the target system
   --verbose                     Increase verbosity
   --version                     Print the assembler version
+  --warnings-as-errors          Treat warnings as errors
 ---------------------------------------------------------------------------
 </verb></tscreen>
 
@@ -359,6 +360,13 @@ Here is a description of all the command line options:
   warning level is 1, and it would probably be silly to set it to
   something lower.
 
+
+  <label id="option--warnings-as-errors">
+  <tag><tt>--warnings-as-errors</tt></tag>
+
+  An error will be generated if any warnings were produced.
+
+
 </descrip>
 <p>
 
diff --git a/doc/ld65.sgml b/doc/ld65.sgml
index 307caeaa4..1ad04b395 100644
--- a/doc/ld65.sgml
+++ b/doc/ld65.sgml
@@ -90,6 +90,7 @@ Long options:
   --start-group                 Start a library group
   --target sys                  Set the target system
   --version                     Print the linker version
+  --warnings-as-errors          Treat warnings as errors
 ---------------------------------------------------------------------------
 </verb></tscreen>
 
@@ -330,6 +331,13 @@ Here is a description of all of the command-line options:
   directory, in the list of directories specified using <tt/--obj-path/, in
   directories given by environment variables, and in a built-in default directory.
 
+
+  <label id="option--warnings-as-errors">
+  <tag><tt>--warnings-as-errors</tt></tag>
+
+  An error will be generated if any warnings were produced.
+
+
 </descrip>
 
 
diff --git a/src/ca65/global.c b/src/ca65/global.c
index a216fc406..81ff68a79 100644
--- a/src/ca65/global.c
+++ b/src/ca65/global.c
@@ -67,6 +67,7 @@ unsigned char LineCont           = 0;   /* Allow line continuation */
 unsigned char LargeAlignment     = 0;   /* Don't warn about large alignments */
 unsigned char RelaxChecks        = 0;   /* Relax a few assembler checks */
 unsigned char StringEscapes      = 0;   /* Allow C-style escapes in strings */
+unsigned char WarningsAsErrors   = 0;   /* Error if any warnings */
 
 /* Emulation features */
 unsigned char DollarIsPC         = 0;   /* Allow the $ symbol as current PC */
diff --git a/src/ca65/global.h b/src/ca65/global.h
index 77d90beca..26877032e 100644
--- a/src/ca65/global.h
+++ b/src/ca65/global.h
@@ -69,6 +69,7 @@ extern unsigned char    LineCont;           /* Allow line continuation */
 extern unsigned char    LargeAlignment;     /* Don't warn about large alignments */
 extern unsigned char    RelaxChecks;        /* Relax a few assembler checks */
 extern unsigned char    StringEscapes;      /* Allow C-style escapes in strings */
+extern unsigned char    WarningsAsErrors;   /* Error if any warnings */
 
 /* Emulation features */
 extern unsigned char    DollarIsPC;         /* Allow the $ symbol as current PC */
diff --git a/src/ca65/main.c b/src/ca65/main.c
index 4146aaf11..9710924bf 100644
--- a/src/ca65/main.c
+++ b/src/ca65/main.c
@@ -656,6 +656,15 @@ static void OptVersion (const char* Opt attribute ((unused)),
 
 
 
+static void OptWarningsAsErrors (const char* Opt attribute ((unused)),
+                                 const char* Arg attribute ((unused)))
+/* Generate an error if any warnings occur */
+{
+    WarningsAsErrors = 1;
+}
+
+
+
 static void DoPCAssign (void)
 /* Start absolute code */
 {
@@ -919,27 +928,28 @@ int main (int argc, char* argv [])
 {
     /* Program long options */
     static const LongOpt OptTab[] = {
-        { "--auto-import",      0,      OptAutoImport           },
-        { "--bin-include-dir",  1,      OptBinIncludeDir        },
-        { "--cpu",              1,      OptCPU                  },
-        { "--create-dep",       1,      OptCreateDep            },
-        { "--create-full-dep",  1,      OptCreateFullDep        },
-        { "--debug",            0,      OptDebug                },
-        { "--debug-info",       0,      OptDebugInfo            },
-        { "--feature",          1,      OptFeature              },
-        { "--help",             0,      OptHelp                 },
-        { "--ignore-case",      0,      OptIgnoreCase           },
-        { "--include-dir",      1,      OptIncludeDir           },
-        { "--large-alignment",  0,      OptLargeAlignment       },
-        { "--list-bytes",       1,      OptListBytes            },
-        { "--listing",          1,      OptListing              },
-        { "--memory-model",     1,      OptMemoryModel          },
-        { "--pagelength",       1,      OptPageLength           },
-        { "--relax-checks",     0,      OptRelaxChecks          },
-        { "--smart",            0,      OptSmart                },
-        { "--target",           1,      OptTarget               },
-        { "--verbose",          0,      OptVerbose              },
-        { "--version",          0,      OptVersion              },
+        { "--auto-import",         0,      OptAutoImport           },
+        { "--bin-include-dir",     1,      OptBinIncludeDir        },
+        { "--cpu",                 1,      OptCPU                  },
+        { "--create-dep",          1,      OptCreateDep            },
+        { "--create-full-dep",     1,      OptCreateFullDep        },
+        { "--debug",               0,      OptDebug                },
+        { "--debug-info",          0,      OptDebugInfo            },
+        { "--feature",             1,      OptFeature              },
+        { "--help",                0,      OptHelp                 },
+        { "--ignore-case",         0,      OptIgnoreCase           },
+        { "--include-dir",         1,      OptIncludeDir           },
+        { "--large-alignment",     0,      OptLargeAlignment       },
+        { "--list-bytes",          1,      OptListBytes            },
+        { "--listing",             1,      OptListing              },
+        { "--memory-model",        1,      OptMemoryModel          },
+        { "--pagelength",          1,      OptPageLength           },
+        { "--relax-checks",        0,      OptRelaxChecks          },
+        { "--smart",               0,      OptSmart                },
+        { "--target",              1,      OptTarget               },
+        { "--verbose",             0,      OptVerbose              },
+        { "--version",             0,      OptVersion              },
+        { "--warnings-as-errors",  0,      OptWarningsAsErrors     },
     };
 
     /* Name of the global name space */
@@ -1144,6 +1154,10 @@ int main (int argc, char* argv [])
         SegDump ();
     }
 
+    if (WarningCount > 0 && WarningsAsErrors) {
+        Error("Warnings as errors");
+    }
+
     /* If we didn't have an errors, finish off the line infos */
     DoneLineInfo ();
 
diff --git a/src/ld65/error.c b/src/ld65/error.c
index 20dfd4537..344e4c1b3 100644
--- a/src/ld65/error.c
+++ b/src/ld65/error.c
@@ -46,6 +46,17 @@
 
 
 
+/*****************************************************************************/
+/*                                   Data                                    */
+/*****************************************************************************/
+
+
+
+/* Statistics */
+unsigned WarningCount   = 0;
+
+
+
 /*****************************************************************************/
 /*                                   Code                                    */
 /*****************************************************************************/
@@ -66,6 +77,9 @@ void Warning (const char* Format, ...)
     fprintf (stderr, "%s: Warning: %s\n", ProgName, SB_GetConstBuf (&S));
 
     SB_Done (&S);
+
+    /* Count warnings */
+    ++WarningCount;
 }
 
 
diff --git a/src/ld65/error.h b/src/ld65/error.h
index 75b8e0bc1..1285ca725 100644
--- a/src/ld65/error.h
+++ b/src/ld65/error.h
@@ -43,6 +43,17 @@
 
 
 
+/*****************************************************************************/
+/*                                   Data                                    */
+/*****************************************************************************/
+
+
+
+/* Statistics */
+extern unsigned WarningCount;
+
+
+
 /*****************************************************************************/
 /*                                   Code                                    */
 /*****************************************************************************/
diff --git a/src/ld65/global.c b/src/ld65/global.c
index 8f43232fe..93dd65958 100644
--- a/src/ld65/global.c
+++ b/src/ld65/global.c
@@ -43,19 +43,20 @@
 
 
 
-const char* OutputName      = "a.out";  /* Name of output file */
-unsigned    OutputNameUsed  = 0;        /* Output name was used by %O */
+const char* OutputName          = "a.out";  /* Name of output file */
+unsigned    OutputNameUsed      = 0;        /* Output name was used by %O */
 
-unsigned ModuleId           = 0;        /* Id for o65 module */
+unsigned ModuleId               = 0;        /* Id for o65 module */
 
 /* Start address */
-unsigned char HaveStartAddr = 0;        /* Start address not given */
-unsigned long StartAddr     = 0x200;    /* Start address */
+unsigned char HaveStartAddr     = 0;        /* Start address not given */
+unsigned long StartAddr         = 0x200;    /* Start address */
 
-unsigned char VerboseMap     = 0;       /* Verbose map file */
-unsigned char AllowMultDef   = 0;       /* Allow multiple definitions */
-unsigned char LargeAlignment = 0;       /* Don't warn about large alignments */
+unsigned char VerboseMap        = 0;        /* Verbose map file */
+unsigned char AllowMultDef      = 0;        /* Allow multiple definitions */
+unsigned char LargeAlignment    = 0;        /* Don't warn about large alignments */
+unsigned char WarningsAsErrors  = 0;        /* Error if any warnings */
 
-const char* MapFileName     = 0;        /* Name of the map file */
-const char* LabelFileName   = 0;        /* Name of the label file */
-const char* DbgFileName     = 0;        /* Name of the debug file */
+const char* MapFileName         = 0;        /* Name of the map file */
+const char* LabelFileName       = 0;        /* Name of the label file */
+const char* DbgFileName         = 0;        /* Name of the debug file */
diff --git a/src/ld65/global.h b/src/ld65/global.h
index a923f6de5..ad85daf0a 100644
--- a/src/ld65/global.h
+++ b/src/ld65/global.h
@@ -44,21 +44,22 @@
 
 
 
-extern const char*      OutputName;     /* Name of output file */
-extern unsigned         OutputNameUsed; /* Output name was used by %O */
+extern const char*      OutputName;        /* Name of output file */
+extern unsigned         OutputNameUsed;    /* Output name was used by %O */
 
-extern unsigned         ModuleId;       /* Id for o65 module */
+extern unsigned         ModuleId;          /* Id for o65 module */
 
-extern unsigned char    HaveStartAddr;  /* True if start address was given */
-extern unsigned long    StartAddr;      /* Start address */
+extern unsigned char    HaveStartAddr;     /* True if start address was given */
+extern unsigned long    StartAddr;         /* Start address */
 
-extern unsigned char    VerboseMap;     /* Verbose map file */
-extern unsigned char    AllowMultDef;   /* Allow multiple definitions */
-extern unsigned char    LargeAlignment; /* Don't warn about large alignments */
+extern unsigned char    VerboseMap;        /* Verbose map file */
+extern unsigned char    AllowMultDef;      /* Allow multiple definitions */
+extern unsigned char    LargeAlignment;    /* Don't warn about large alignments */
+extern unsigned char    WarningsAsErrors;  /* Error if any warnings */
 
-extern const char*      MapFileName;    /* Name of the map file */
-extern const char*      LabelFileName;  /* Name of the label file */
-extern const char*      DbgFileName;    /* Name of the debug file */
+extern const char*      MapFileName;       /* Name of the map file */
+extern const char*      LabelFileName;     /* Name of the label file */
+extern const char*      DbgFileName;       /* Name of the debug file */
 
 
 
diff --git a/src/ld65/main.c b/src/ld65/main.c
index f2415a914..70e9c84d1 100644
--- a/src/ld65/main.c
+++ b/src/ld65/main.c
@@ -559,6 +559,15 @@ static void OptVersion (const char* Opt attribute ((unused)),
 
 
 
+static void OptWarningsAsErrors (const char* Opt attribute ((unused)),
+                                 const char* Arg attribute ((unused)))
+/* Generate an error if any warnings occur */
+{
+    WarningsAsErrors = 1;
+}
+
+
+
 static void OptMultDef (const char* Opt attribute ((unused)),
                         const char* Arg attribute ((unused)))
 /* Set flag to allow multiple definitions of a global symbol */
@@ -637,6 +646,7 @@ static void ParseCommandLine(void)
         { "--start-group",               0,      CmdlOptStartGroup       },
         { "--target",                    1,      CmdlOptTarget           },
         { "--version",                   0,      OptVersion              },
+        { "--warnings-as-errors",        0,      OptWarningsAsErrors     },
     };
 
     unsigned I;
@@ -845,6 +855,10 @@ int main (int argc, char* argv [])
                (MemoryAreaOverflows > 1) ? 's' : ' ');
     }
 
+    if (WarningCount > 0 && WarningsAsErrors) {
+        Error("Warnings as errors");
+    }
+
     /* Create the output file */
     CfgWriteTarget ();
 
diff --git a/src/ld65/scanner.c b/src/ld65/scanner.c
index 718951aa5..5f53e5765 100644
--- a/src/ld65/scanner.c
+++ b/src/ld65/scanner.c
@@ -95,6 +95,9 @@ void CfgWarning (const FilePos* Pos, const char* Format, ...)
     Warning ("%s:%u: %s",
              GetString (Pos->Name), Pos->Line, SB_GetConstBuf (&Buf));
     SB_Done (&Buf);
+
+    /* Count warnings */
+    ++WarningCount;
 }