diff --git a/spec/Plugin/QueryDefaultsPluginSpec.php b/spec/Plugin/QueryDefaultsPluginSpec.php
index e4c88d0..82d9125 100644
--- a/spec/Plugin/QueryDefaultsPluginSpec.php
+++ b/spec/Plugin/QueryDefaultsPluginSpec.php
@@ -39,4 +39,21 @@ public function it_sets_the_default_header(RequestInterface $request, UriInterfa
         }, function () {
         });
     }
+
+    public function it_does_not_replace_existing_request_value(RequestInterface $request, UriInterface $uri)
+    {
+        $this->beConstructedWith([
+            'foo' => 'fooDefault',
+            'bar' => 'barDefault',
+        ]);
+
+        $request->getUri()->shouldBeCalled()->willReturn($uri);
+        $uri->getQuery()->shouldBeCalled()->willReturn('foo=new');
+        $uri->withQuery('foo=new&bar=barDefault')->shouldBeCalled()->willReturn($uri);
+        $request->withUri($uri)->shouldBeCalled()->willReturn($request);
+
+        $this->handleRequest($request, function () {
+        }, function () {
+        });
+    }
 }
diff --git a/src/Plugin/QueryDefaultsPlugin.php b/src/Plugin/QueryDefaultsPlugin.php
index 6c1e32c..d9c06d6 100644
--- a/src/Plugin/QueryDefaultsPlugin.php
+++ b/src/Plugin/QueryDefaultsPlugin.php
@@ -33,21 +33,14 @@ public function __construct(array $queryParams)
      */
     public function handleRequest(RequestInterface $request, callable $next, callable $first)
     {
-        foreach ($this->queryParams as $name => $value) {
-            $uri = $request->getUri();
-            $array = [];
-            parse_str($uri->getQuery(), $array);
-
-            // If query value is not found
-            if (!isset($array[$name])) {
-                $array[$name] = $value;
-
-                // Create a new request with the new URI with the added query param
-                $request = $request->withUri(
-                    $uri->withQuery(http_build_query($array))
-                );
-            }
-        }
+        $uri = $request->getUri();
+
+        parse_str($uri->getQuery(), $query);
+        $query += $this->queryParams;
+
+        $request = $request->withUri(
+            $uri->withQuery(http_build_query($query))
+        );
 
         return $next($request);
     }