diff --git a/src/ca65/pseudo.c b/src/ca65/pseudo.c
index 3128231ec..60d78d643 100644
--- a/src/ca65/pseudo.c
+++ b/src/ca65/pseudo.c
@@ -127,6 +127,11 @@ static unsigned char OptionalAddrSize (void)
     if (Tok == TOK_COLON) {
         NextTok ();
         AddrSize = ParseAddrSize ();
+        if (!ValidAddrSizeForCPU (AddrSize)) {
+            /* Print an error and reset to default */
+            Error ("Invalid address size specification for current CPU");
+            AddrSize = ADDR_SIZE_DEFAULT;
+        }
         NextTok ();
     }
     return AddrSize;
diff --git a/src/common/cpu.c b/src/common/cpu.c
index 064614253..e3335f2bd 100644
--- a/src/common/cpu.c
+++ b/src/common/cpu.c
@@ -6,8 +6,8 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 2003-2005, Ullrich von Bassewitz                                      */
-/*                Römerstrasse 52                                            */
+/* (C) 2003-2009, Ullrich von Bassewitz                                      */
+/*                Roemerstrasse 52                                           */
 /*                D-70794 Filderstadt                                        */
 /* EMail:         uz@cc65.org                                                */
 /*                                                                           */
@@ -34,6 +34,8 @@
 
 
 /* common */
+#include "addrsize.h"
+#include "check.h"
 #include "cpu.h"
 #include "strutil.h"
 
@@ -82,6 +84,37 @@ const unsigned CPUIsets[CPU_COUNT] = {
 
 
 
+int ValidAddrSizeForCPU (unsigned char AddrSize)
+/* Check if the given address size is valid for the current CPU */
+{
+    switch (AddrSize) {
+        case ADDR_SIZE_DEFAULT:
+            /* Always supported */
+            return 1;
+
+        case ADDR_SIZE_ZP:
+            /* Not supported by None and Sweet16 */
+            return (CPU != CPU_NONE && CPU != CPU_SWEET16);
+
+        case ADDR_SIZE_ABS:
+            /* Not supported by None */
+            return (CPU != CPU_NONE);
+
+        case ADDR_SIZE_FAR:
+            /* Only supported by 65816 */
+            return (CPU == CPU_65816);
+
+        case ADDR_SIZE_LONG:
+            /* Not supported by any CPU */
+            return 0;
+
+        default:
+            FAIL ("Invalid address size");
+    }
+}
+
+
+
 cpu_t FindCPU (const char* Name)
 /* Find a CPU by name and return the target id. CPU_UNKNOWN is returned if
  * the given name is no valid target.
diff --git a/src/common/cpu.h b/src/common/cpu.h
index 6a6cd73d7..16dd0e309 100644
--- a/src/common/cpu.h
+++ b/src/common/cpu.h
@@ -6,8 +6,8 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 2003-2005, Ullrich von Bassewitz                                      */
-/*                Römerstrasse 52                                            */
+/* (C) 2003-2009, Ullrich von Bassewitz                                      */
+/*                Roemerstrasse 52                                           */
 /*                D-70794 Filderstadt                                        */
 /* EMail:         uz@cc65.org                                                */
 /*                                                                           */
@@ -89,6 +89,9 @@ extern const unsigned CPUIsets[CPU_COUNT];
 
 
 
+int ValidAddrSizeForCPU (unsigned char AddrSize);
+/* Check if the given address size is valid for the current CPU */
+
 cpu_t FindCPU (const char* Name);
 /* Find a CPU by name and return the target id. CPU_UNKNOWN is returned if
  * the given name is no valid target.