diff --git a/engine/engine.go b/engine/engine.go
index 06e05a77..d3f410a1 100644
--- a/engine/engine.go
+++ b/engine/engine.go
@@ -64,6 +64,7 @@ type (
 		Path() string
 		SetPath(string)
 		QueryValue(string) string
+		QueryString() string
 	}
 
 	// Config defines engine configuration.
diff --git a/engine/fasthttp/header.go b/engine/fasthttp/header.go
index c3c3e93d..36417102 100644
--- a/engine/fasthttp/header.go
+++ b/engine/fasthttp/header.go
@@ -42,6 +42,7 @@ func (h *RequestHeader) reset(hdr *fasthttp.RequestHeader) {
 
 // Add implements `engine.Header#Add` method.
 func (h *ResponseHeader) Add(key, val string) {
+	// TODO: https://github.com/valyala/fasthttp/issues/69
 	// h.header.Add(key, val)
 }
 
diff --git a/engine/fasthttp/url.go b/engine/fasthttp/url.go
index 1e8db125..0cb16e03 100644
--- a/engine/fasthttp/url.go
+++ b/engine/fasthttp/url.go
@@ -26,6 +26,11 @@ func (u *URL) QueryValue(name string) string {
 	return string(u.QueryArgs().Peek(name))
 }
 
+// QueryString implements `engine.URL#QueryString` method.
+func (u *URL) QueryString() string {
+	return string(u.URI.QueryString())
+}
+
 func (u *URL) reset(uri *fasthttp.URI) {
 	u.URI = uri
 }
diff --git a/engine/standard/url.go b/engine/standard/url.go
index c2f743ce..06e0c6c5 100644
--- a/engine/standard/url.go
+++ b/engine/standard/url.go
@@ -28,6 +28,11 @@ func (u *URL) QueryValue(name string) string {
 	return u.query.Get(name)
 }
 
+// QueryString implements `engine.URL#QueryString` method.
+func (u *URL) QueryString() string {
+	return u.URL.RawQuery
+}
+
 func (u *URL) reset(url *url.URL) {
 	u.URL = url
 }
diff --git a/test/url.go b/test/url.go
index 8f64813f..277df0e4 100644
--- a/test/url.go
+++ b/test/url.go
@@ -28,6 +28,10 @@ func (u *URL) QueryValue(name string) string {
 	return u.query.Get(name)
 }
 
+func (u *URL) QueryString() string {
+	return u.url.RawQuery
+}
+
 func (u *URL) Object() interface{} {
 	return u.url
 }