diff --git a/AUTHORS.rst b/AUTHORS.rst
index 12445881..078ed993 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -119,3 +119,4 @@ Patches and Suggestions
 - Jonatan Heyman
 - David Bonner <dbonner@gmail.com> @rascalking
 - Vinod Chandru
+- Johnny Goodnow <j.goodnow29@gmail.com>
diff --git a/requests/models.py b/requests/models.py
index 99260453..42351417 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -386,13 +386,14 @@ class PreparedRequest(RequestEncodingMixin, RequestHooksMixin):
         self.body = body
 
     def prepare_content_length(self, body):
-        self.headers['Content-Length'] = '0'
         if hasattr(body, 'seek') and hasattr(body, 'tell'):
             body.seek(0, 2)
             self.headers['Content-Length'] = str(body.tell())
             body.seek(0, 0)
         elif body is not None:
             self.headers['Content-Length'] = str(len(body))
+        elif self.method not in ('GET', 'HEAD'):
+            self.headers['Content-Length'] = '0'
 
     def prepare_auth(self, auth):
         """Prepares the given HTTP auth data."""
diff --git a/test_requests.py b/test_requests.py
index c974e980..312c955d 100644
--- a/test_requests.py
+++ b/test_requests.py
@@ -58,6 +58,13 @@ class RequestsTestCase(unittest.TestCase):
         assert pr.body == 'life=42'
 
 
+    def test_no_content_length(self):
+        get_req = requests.Request('GET', httpbin('get')).prepare()
+        self.assertTrue('Content-Length' not in get_req.headers)
+        head_req = requests.Request('HEAD', httpbin('head')).prepare()
+        self.assertTrue('Content-Length' not in head_req.headers)
+
+
     def test_path_is_not_double_encoded(self):
         request = requests.Request('GET', "http://0.0.0.0/get/test case").prepare()