diff --git a/plugins/Math.py b/plugins/Math.py
index d88e7e44a..01ce0fb20 100644
--- a/plugins/Math.py
+++ b/plugins/Math.py
@@ -152,6 +152,8 @@ class Math(callbacks.Privmsg):
             irc.error(msg, 'Go get scanez, this is a *real* math problem!')
         except TypeError:
             irc.error(msg, 'Something in there wasn\'t a valid number.')
+        except NameError, e:
+            irc.error(msg, '%s is not a defined function.' % str(e).split()[1])
         except Exception, e:
             irc.error(msg, debug.exnToString(e))
 
@@ -194,7 +196,11 @@ class Math(callbacks.Privmsg):
                     arg2 = stack.pop()
                     arg1 = stack.pop()
                     s = '%s%s%s' % (arg1, arg, arg2)
-                    stack.append(eval(s, self._mathEnv, self._mathEnv))
+                    try:
+                        stack.append(eval(s, self._mathEnv, self._mathEnv))
+                    except SyntaxError:
+                        irc.error(msg, '%r is not a defined function.' % arg)
+                        return
         if len(stack) == 1:
             irc.reply(msg, str(self._complexToString(complex(stack[0]))))
         else:
diff --git a/test/test_Math.py b/test/test_Math.py
index b0df510e1..564a279e9 100644
--- a/test/test_Math.py
+++ b/test/test_Math.py
@@ -47,12 +47,18 @@ class MathTestCase(PluginTestCase, PluginDocumentation):
 ##         self.assertNotError('calc log(8,2)')
 ##         self.assertNotError('calc log(8,2)')
 
+    def testCalcNoNameError(self):
+        self.assertNotRegexp('calc foobar(x)', 'NameError')
+        
     def testRpn(self):
         self.assertResponse('rpn 5 2 +', '7')
         self.assertResponse('rpn 1 2 3 +', 'Stack: [1, 5]')
         self.assertResponse('rpn 1 dup', 'Stack: [1, 1]')
         self.assertResponse('rpn 2 3 4 + -', str(2-7))
         self.assertNotError('rpn 2 degrees')
+
+    def testRpmNoSyntaxError(self):
+        self.assertNotRegexp('rpn 2 3 foobar', 'SyntaxError')
         
     def testConvert(self):
         self.assertResponse('convert 1 m to cm', '100.0 cm')