diff --git a/src/Microsoft.AspNet.Security.OAuthBearer/OAuthBearerAuthenticationHandler.cs b/src/Microsoft.AspNet.Security.OAuthBearer/OAuthBearerAuthenticationHandler.cs
index b81af0c735..c1f03a074c 100644
--- a/src/Microsoft.AspNet.Security.OAuthBearer/OAuthBearerAuthenticationHandler.cs
+++ b/src/Microsoft.AspNet.Security.OAuthBearer/OAuthBearerAuthenticationHandler.cs
@@ -60,6 +60,13 @@ namespace Microsoft.AspNet.Security.OAuthBearer
                 }
 
                 string authorization = Request.Headers.Get("Authorization");
+
+                // If no authorization header found, nothing to process further
+                if (String.IsNullOrEmpty(authorization))
+                {
+                    return null;
+                }
+
                 if (authorization.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase))
                 {
                      token = authorization.Substring("Bearer ".Length).Trim();
diff --git a/test/Microsoft.AspNet.Security.Test/OAuthBearer/OAuthBearerMiddlewareTests.cs b/test/Microsoft.AspNet.Security.Test/OAuthBearer/OAuthBearerMiddlewareTests.cs
index eff8e28841..2139f56306 100644
--- a/test/Microsoft.AspNet.Security.Test/OAuthBearer/OAuthBearerMiddlewareTests.cs
+++ b/test/Microsoft.AspNet.Security.Test/OAuthBearer/OAuthBearerMiddlewareTests.cs
@@ -66,6 +66,22 @@ namespace Microsoft.AspNet.Security.OAuthBearer
             return Task.FromResult<object>(null);
         }
 
+        [Fact]
+        public async Task NoHeaderReceived()
+        {
+            var server = CreateServer(options => { });
+            var response = await SendAsync(server, "http://example.com/oauth");
+            response.Response.StatusCode.ShouldBe(HttpStatusCode.OK);
+        }
+
+        [Fact]
+        public async Task HeaderWithoutBearerReceived()
+        {
+            var server = CreateServer(options => { });
+            var response = await SendAsync(server, "http://example.com/oauth","Token");
+            response.Response.StatusCode.ShouldBe(HttpStatusCode.OK);
+        }
+
         [Fact]
         public async Task CustomTokenReceived()
         {
@@ -235,4 +251,4 @@ namespace Microsoft.AspNet.Security.OAuthBearer
             public XElement ResponseElement { get; set; }
         }
     }
-}
\ No newline at end of file
+}