diff --git a/tests/unit/test_request.py b/tests/unit/test_request.py
index adecee6..fdc2e89 100644
--- a/tests/unit/test_request.py
+++ b/tests/unit/test_request.py
@@ -4,3 +4,18 @@ from vcr.request import Request
 def test_str():
     req = Request('GET', 'http://www.google.com:80/', '', {})
     str(req) == '<Request (GET) http://www.google.com:80/>'
+
+
+def test_headers():
+    headers = {'X-Header1': ['h1'], 'X-Header2': 'h2'}
+    req = Request('GET', 'http://go.com:80/', '', headers)
+    assert req.headers == {'X-Header1': ['h1'], 'X-Header2': ['h2']}
+
+    req.add_header('X-Header1', 'h11')
+    assert req.headers == {'X-Header1': ['h1', 'h11'], 'X-Header2': ['h2']}
+
+
+def test_flat_headers_dict():
+    headers = {'X-Header1': ['h1', 'h11'], 'X-Header2': ['h2']}
+    req = Request('GET', 'http://go.com:80/', '', headers)
+    assert req.flat_headers_dict() == {'X-Header1': 'h1', 'X-Header2': 'h2'}
diff --git a/vcr/request.py b/vcr/request.py
index 10b9fb5..6d48a56 100644
--- a/vcr/request.py
+++ b/vcr/request.py
@@ -7,10 +7,16 @@ class Request(object):
         self.method = method
         self.uri = uri
         self.body = body
-        self.headers = headers
+        self.headers = {}
+        for key in headers:
+            self.add_header(key, headers[key])
 
     def add_header(self, key, value):
-        self.headers[key] = value
+        value = list(value) if isinstance(value, (tuple, list)) else [value]
+        self.headers.setdefault(key, []).extend(value)
+
+    def flat_headers_dict(self):
+        return {key: self.headers[key][0] for key in self.headers}
 
     @property
     def scheme(self):
@@ -54,7 +60,7 @@ class Request(object):
             'method': self.method,
             'uri': self.uri,
             'body': self.body,
-            'headers': dict(self.headers),
+            'headers': self.headers,
         }
 
     @classmethod
diff --git a/vcr/stubs/__init__.py b/vcr/stubs/__init__.py
index 77391b2..fc14919 100644
--- a/vcr/stubs/__init__.py
+++ b/vcr/stubs/__init__.py
@@ -225,7 +225,7 @@ class VCRConnection:
                 method=self._vcr_request.method,
                 url=self._url(self._vcr_request.uri),
                 body=self._vcr_request.body,
-                headers=dict(self._vcr_request.headers or {})
+                headers=self._vcr_request.flat_headers_dict(),
             )
 
             # get the response