diff --git a/httpretty/core.py b/httpretty/core.py
index 3f861b8..de7b93b 100644
--- a/httpretty/core.py
+++ b/httpretty/core.py
@@ -622,6 +622,7 @@ class Entry(BaseClass):
             if got is None:
                 continue
 
+            igot = None
             try:
                 igot = int(got)
             except (ValueError, TypeError):
@@ -630,7 +631,7 @@ class Entry(BaseClass):
                     'with "%r" which is not a number' % got)
                 return
 
-            if igot > self.body_length:
+            if igot and igot > self.body_length:
                 raise HTTPrettyError(
                     'HTTPretty got inconsistent parameters. The header '
                     'Content-Length you registered expects size "%d" but '
diff --git a/tests/functional/test_urllib2.py b/tests/functional/test_urllib2.py
index cd69356..dde54a3 100644
--- a/tests/functional/test_urllib2.py
+++ b/tests/functional/test_urllib2.py
@@ -133,6 +133,7 @@ def test_httpretty_should_allow_forcing_headers_urllib2():
                            body="this is supposed to be the response",
                            forcing_headers={
                                'Content-Type': 'application/xml',
+                               'Content-Length': '35a',
                            })
 
     request = urlopen('http://github.com')
@@ -141,6 +142,7 @@ def test_httpretty_should_allow_forcing_headers_urllib2():
 
     expect(headers).to.equal({
         'content-type': 'application/xml',
+        'content-length': '35a',
     })