diff -r 097554712637 Lib/idlelib/OutputWindow.py
--- a/Lib/idlelib/OutputWindow.py	Wed Apr 03 00:42:24 2013 -0500
+++ b/Lib/idlelib/OutputWindow.py	Wed Apr 03 19:41:03 2013 -0500
@@ -43,7 +43,28 @@
             except UnicodeError:
                 # some other encoding; let Tcl deal with it
                 pass
-        self.text.insert(mark, s, tags)
+
+        # manual line wrapping
+        wrap_index = 80
+        lines = s.split('\n')
+
+        # starting column
+        col = int(self.text.index(mark).split('.')[1])
+
+        # characters remaining before wrap
+        remaining = wrap_index - col
+
+        wrap = []
+        for line in lines:
+            line_wrap = []
+            i = 0
+            while i < len(line):
+                line_wrap.append(line[i:i+remaining])
+                i += wrap_index
+                remaining = wrap_index
+            wrap.append('\n'.join(line_wrap))
+        self.text.insert(mark, '\n'.join(wrap), tags)
+
         self.text.see(mark)
         self.text.update()