diff --git a/requests/models.py b/requests/models.py
index ce4e284e64..48ac38b270 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -785,6 +785,7 @@ def iter_lines(self, chunk_size=ITER_CHUNK_SIZE, decode_unicode=None, delimiter=
         """
 
         pending = None
+        carriage_return = u'\r' if decode_unicode else b'\r'
 
         for chunk in self.iter_content(chunk_size=chunk_size, decode_unicode=decode_unicode):
 
@@ -798,6 +799,8 @@ def iter_lines(self, chunk_size=ITER_CHUNK_SIZE, decode_unicode=None, delimiter=
 
             if lines and lines[-1] and chunk and lines[-1][-1] == chunk[-1]:
                 pending = lines.pop()
+            elif not delimiter and lines and chunk.endswith(carriage_return):
+                pending = lines.pop() + carriage_return
             else:
                 pending = None
 
@@ -805,6 +808,8 @@ def iter_lines(self, chunk_size=ITER_CHUNK_SIZE, decode_unicode=None, delimiter=
                 yield line
 
         if pending is not None:
+            if not delimiter:
+                pending = pending.rstrip(carriage_return)
             yield pending
 
     @property
diff --git a/tests/test_requests.py b/tests/test_requests.py
index b374747427..595a1a042d 100644
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -3,6 +3,7 @@
 """Tests for Requests."""
 
 from __future__ import division
+import base64
 import json
 import os
 import pickle
@@ -1738,6 +1739,15 @@ def test_response_iter_lines(self, httpbin):
         next(it)
         assert len(list(it)) == 3
 
+    @pytest.mark.parametrize('chunk', (3, 4))
+    @pytest.mark.parametrize('decode', (True, False))
+    def test_response_iter_lines_crlf_across_chunks(self, httpbin, chunk, decode):
+        b64_body = base64.b64encode(b'one\r\ntwo\r\rthree\r').decode('ascii')
+        r = requests.get(httpbin('base64/' + b64_body), stream=True)
+
+        it = r.iter_lines(chunk_size=chunk, decode_unicode=decode)
+        assert [len(line) for line in it] == [3, 3, 0, 5]
+
     def test_response_context_manager(self, httpbin):
         with requests.get(httpbin('stream/4'), stream=True) as response:
             assert isinstance(response, requests.Response)