diff --git a/NEWS b/NEWS
index 9dbf75e0..5263e3db 100644
--- a/NEWS
+++ b/NEWS
@@ -19,6 +19,7 @@ NEWS
   * fixed too aggresive caching of nested conditionals (#41)
   * fixed possible overflow in unix-socket path checks on BSD (#713)
   * fixed extra Content-Length header on 1xx, 204 and 304 (#1002)
+  * fixed handling of duplicate If-Modified-Since to return 304 
   * removed config-check if passwd files exist (#1188)
   
 
diff --git a/src/request.c b/src/request.c
index c195388e..42988732 100644
--- a/src/request.c
+++ b/src/request.c
@@ -922,6 +922,9 @@ int http_request_parse(server *srv, connection *con) {
 								} else if (0 == strcasecmp(con->request.http_if_modified_since,
 											ds->value->ptr)) {
 									/* ignore it if they are the same */
+
+									ds->free((data_unset *)ds);
+									ds = NULL;
 								} else {
 									con->http_status = 400;
 									con->keep_alive = 0;
@@ -977,7 +980,7 @@ int http_request_parse(server *srv, connection *con) {
 								}
 							}
 
-							array_insert_unique(con->request.headers, (data_unset *)ds);
+							if (ds) array_insert_unique(con->request.headers, (data_unset *)ds);
 						} else {
 							/* empty header-fields are not allowed by HTTP-RFC, we just ignore them */
 						}
diff --git a/tests/request.t b/tests/request.t
index 8ece7218..f7bc19c8 100755
--- a/tests/request.t
+++ b/tests/request.t
@@ -339,12 +339,12 @@ $t->{RESPONSE} = [ { 'HTTP-Protocol' => 'HTTP/1.0', 'HTTP-Status' => 400 } ];
 ok($tf->handle_http($t) == 0, 'HEAD with Content-Length');
 
 $t->{REQUEST}  = ( <<EOF
-GET / HTTP/1.0
-If-Modified-Since: Sun, 1970 Jan 01 00:00:01 GMT
-If-Modified-Since: Sun, 1970 Jan 01 00:00:01 GMT
+GET /index.html HTTP/1.0
+If-Modified-Since: Sun, 01 Jan 2100 00:00:02 GMT
+If-Modified-Since: Sun, 01 Jan 2100 00:00:02 GMT
 EOF
  );
-$t->{RESPONSE} = [ { 'HTTP-Protocol' => 'HTTP/1.0', 'HTTP-Status' => 200 } ];
+$t->{RESPONSE} = [ { 'HTTP-Protocol' => 'HTTP/1.0', 'HTTP-Status' => 304 } ];
 ok($tf->handle_http($t) == 0, 'Duplicate If-Mod-Since, with equal timestamps');
 
 $t->{REQUEST}  = ( "GET / HTTP/1.0\r\nIf-Modified-Since: \0\r\n\r\n" );