diff --git a/uri.go b/uri.go
index 464ccd7..6249f44 100644
--- a/uri.go
+++ b/uri.go
@@ -268,12 +268,7 @@ func (u *URI) parse(host, uri []byte, h *RequestHeader) {
 
 func normalizePath(dst, src []byte) []byte {
 	dst = dst[:0]
-
-	// add leading slash
-	if len(src) == 0 || src[0] != '/' {
-		dst = append(dst, '/')
-	}
-
+	dst = addLeadingSlash(dst, src)
 	dst = decodeArgAppend(dst, src, false)
 
 	// remove duplicate slashes
diff --git a/uri_unix.go b/uri_unix.go
new file mode 100644
index 0000000..631712a
--- /dev/null
+++ b/uri_unix.go
@@ -0,0 +1,15 @@
+// +build !windows
+
+package fasthttp
+
+import "bytes"
+
+
+func addLeadingSlash(dst, src []byte) []byte {
+	// add leading slash for unix paths
+	if len(src) == 0 || src[0] != '/' {
+		dst = append(dst, '/')
+	}
+
+	return dst
+}
diff --git a/uri_windows.go b/uri_windows.go
new file mode 100644
index 0000000..c7980c8
--- /dev/null
+++ b/uri_windows.go
@@ -0,0 +1,12 @@
+// +build windows
+
+package fasthttp
+
+func addLeadingSlash(dst, src []byte) []byte {
+	// zero length and "C:/" case
+	if len(src) == 0 || (len(src) > 2 && src[1] != ':') {
+		dst = append(dst, '/')
+	}
+
+	return dst
+}
\ No newline at end of file
diff --git a/uri_windows_test.go b/uri_windows_test.go
new file mode 100644
index 0000000..61d1a2c
--- /dev/null
+++ b/uri_windows_test.go
@@ -0,0 +1,12 @@
+// +build windows
+
+package fasthttp
+
+import "testing"
+
+func TestURIPathNormalizeIssue86(t *testing.T) {
+	// see https://github.com/valyala/fasthttp/issues/86
+	var u URI
+
+	testURIPathNormalize(t, &u, `C:\a\b\c\fs.go`, `C:\a\b\c\fs.go`)
+}