diff --git a/py65/monitor.py b/py65/monitor.py
index 36309e9..9f235a4 100644
--- a/py65/monitor.py
+++ b/py65/monitor.py
@@ -53,8 +53,8 @@ class Monitor(cmd.Cmd):
             shortopts = 'hm:l:r:g:'
             longopts = ['help', 'mpu=', 'load=', 'rom=', 'goto=']
             options, args = getopt.getopt(argv[1:], shortopts, longopts)
-        except getopt.GetoptError, err:
-            self._output(str(err))
+        except getopt.GetoptError as exc:
+            self._output(str(exc))
             self._usage()
             self._exit(1)
 
@@ -104,7 +104,7 @@ class Monitor(cmd.Cmd):
             result = cmd.Cmd.onecmd(self, line)
         except KeyboardInterrupt:
             self._output("Interrupt")
-        except Exception, e:
+        except Exception:
             (file, fun, line), t, v, tbinfo = compact_traceback()
             error = 'Error: %s, %s: file: %s line: %s' % (t, v, file, line)
             self._output(error)
@@ -506,8 +506,8 @@ class Monitor(cmd.Cmd):
                     if len(register) == 1:
                         intval &= self.byteMask
                     setattr(self._mpu, register, intval)
-                except KeyError, why:
-                    self._output(why[0])
+                except KeyError as exc:
+                    self._output(exc[0])
 
     def help_cd(self):
         self._output("cd <directory>")
@@ -519,8 +519,8 @@ class Monitor(cmd.Cmd):
 
         try:
             os.chdir(args)
-        except OSError, why:
-            msg = "Cannot change directory: [%d] %s" % (why[0], why[1])
+        except OSError as exc:
+            msg = "Cannot change directory: [%d] %s" % (exc[0], exc[1])
             self._output(msg)
         self.do_pwd()
 
@@ -549,8 +549,8 @@ class Monitor(cmd.Cmd):
                 f = urllib2.urlopen(filename)
                 bytes = f.read()
                 f.close()
-            except (urllib2.URLError, urllib2.HTTPError), why:
-                msg = "Cannot fetch remote file: %s" % str(why)
+            except (urllib2.URLError, urllib2.HTTPError) as exc:
+                msg = "Cannot fetch remote file: %s" % str(exc)
                 self._output(msg)
                 return
         else:
@@ -558,8 +558,8 @@ class Monitor(cmd.Cmd):
                 f = open(filename, 'rb')
                 bytes = f.read()
                 f.close()
-            except (OSError, IOError), why:
-                msg = "Cannot load file: [%d] %s" % (why[0], why[1])
+            except (OSError, IOError) as exc:
+                msg = "Cannot load file: [%d] %s" % (exc[0], exc[1])
                 self._output(msg)
                 return
 
@@ -600,8 +600,8 @@ class Monitor(cmd.Cmd):
                 for shift in range(self.byteWidth - 8, -1, -8):
                     f.write(chr((byte >> shift) & 0xff))
             f.close()
-        except (OSError, IOError), why:
-            msg = "Cannot save file: [%d] %s" % (why[0], why[1])
+        except (OSError, IOError) as exc:
+            msg = "Cannot save file: [%d] %s" % (exc[0], exc[1])
             self._output(msg)
             return
 
diff --git a/py65/tests/utils/test_addressing.py b/py65/tests/utils/test_addressing.py
index a4ce268..039dcc5 100644
--- a/py65/tests/utils/test_addressing.py
+++ b/py65/tests/utils/test_addressing.py
@@ -49,8 +49,8 @@ class AddressParserTests(unittest.TestCase):
         try:
             parser.number('bad_label')
             self.fail()
-        except KeyError, why:
-            self.assertEqual('Label not found: bad_label', why[0])
+        except KeyError as exc:
+            self.assertEqual('Label not found: bad_label', exc[0])
 
     def test_number_label_hex_offset(self):
         parser = AddressParser()
@@ -95,8 +95,8 @@ class AddressParserTests(unittest.TestCase):
         try:
             parser.number('bad_label+3')
             self.fail()
-        except KeyError, why:
-            self.assertEqual('Label not found: bad_label', why[0])
+        except KeyError as exc:
+            self.assertEqual('Label not found: bad_label', exc[0])
 
     def test_number_bad_label_syntax(self):
         parser = AddressParser()
@@ -104,8 +104,8 @@ class AddressParserTests(unittest.TestCase):
         try:
             parser.number('#$foo')
             self.fail()
-        except KeyError, why:
-            self.assertEqual('Label not found: #$foo', why[0])
+        except KeyError as exc:
+            self.assertEqual('Label not found: #$foo', exc[0])
 
     def test_number_constrains_address_at_zero_or_above(self):
         parser = AddressParser()
diff --git a/py65/tests/utils/test_hexdump.py b/py65/tests/utils/test_hexdump.py
index 0bedce7..9c29233 100644
--- a/py65/tests/utils/test_hexdump.py
+++ b/py65/tests/utils/test_hexdump.py
@@ -29,55 +29,55 @@ class HexdumpLoaderTests(unittest.TestCase):
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Start address was not found in data'
-            self.assert_(why[0].startswith('Start address'))
+            self.assert_(exc[0].startswith('Start address'))
 
     def test_raises_when_start_address_is_invalid(self):
         text = 'oops: aa bb cc'
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Could not parse address: oops'
-            self.assertEqual(msg, why[0])
+            self.assertEqual(msg, exc[0])
 
     def test_raises_when_start_address_is_too_short(self):
         text = '01: aa bb cc'
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Expected address to be 2 bytes, got 1'
-            self.assertEqual(msg, why[0])
+            self.assertEqual(msg, exc[0])
 
     def test_raises_when_start_address_is_too_long(self):
         text = '010304: aa bb cc'
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Expected address to be 2 bytes, got 3'
-            self.assertEqual(msg, why[0])
+            self.assertEqual(msg, exc[0])
 
     def test_raises_when_next_address_is_unexpected(self):
         text = "c000: aa\nc002: cc"
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Non-contigous block detected.  Expected next ' \
                   'address to be $c001, label was $c002'
-            self.assertEqual(msg, why[0])
+            self.assertEqual(msg, exc[0])
 
     def test_raises_when_data_is_invalid(self):
         text = 'c000: foo'
         try:
             Loader(text)
             self.fail()
-        except ValueError, why:
+        except ValueError as exc:
             msg = 'Could not parse data: foo'
-            self.assertEqual(msg, why[0])
+            self.assertEqual(msg, exc[0])
 
     def test_loads_data_without_dollar_signs(self):
         text = 'c000: aa bb'