diff --git a/signature.go b/signature.go
index 53c38bc..afb7d63 100644
--- a/signature.go
+++ b/signature.go
@@ -132,10 +132,6 @@ func (s *Signature) sign(key string, r *http.Request) error {
 
 // IsValid validates this signature for the given key
 func (s Signature) IsValid(key string, r *http.Request) bool {
-	if !s.Headers.hasDate() {
-		return false
-	}
-
 	sig, err := s.calculateSignature(key, r)
 	if err != nil {
 		return false