diff --git a/graphsync.go b/graphsync.go
index 69392119..3dc6a990 100644
--- a/graphsync.go
+++ b/graphsync.go
@@ -137,6 +137,13 @@ func (e RequestCancelledErr) Error() string {
 	return "Request Failed - Responder Cancelled"
 }
 
+// RequestNotFoundErr indicates that a request with a particular request ID was not found
+type RequestNotFoundErr struct{}
+
+func (e RequestNotFoundErr) Error() string {
+	return "request not found"
+}
+
 var (
 	// ErrExtensionAlreadyRegistered means a user extension can be registered only once
 	ErrExtensionAlreadyRegistered = errors.New("extension already registered")
diff --git a/requestmanager/requestmanager.go b/requestmanager/requestmanager.go
index 9af6c715..5508b7bc 100644
--- a/requestmanager/requestmanager.go
+++ b/requestmanager/requestmanager.go
@@ -449,7 +449,7 @@ func (crm *cancelRequestMessage) handle(rm *RequestManager) {
 	if !ok {
 		if crm.onTerminated != nil {
 			select {
-			case crm.onTerminated <- errors.New("request not found"):
+			case crm.onTerminated <- graphsync.RequestNotFoundErr{}:
 			case <-rm.ctx.Done():
 			}
 		}
@@ -659,7 +659,7 @@ func (rm *RequestManager) sendRequest(p peer.ID, request gsmsg.GraphSyncRequest)
 func (urm *unpauseRequestMessage) unpause(rm *RequestManager) error {
 	inProgressRequestStatus, ok := rm.inProgressRequestStatuses[urm.id]
 	if !ok {
-		return errors.New("request not found")
+		return graphsync.RequestNotFoundErr{}
 	}
 	if !inProgressRequestStatus.paused {
 		return errors.New("request is not paused")
@@ -685,7 +685,7 @@ func (urm *unpauseRequestMessage) handle(rm *RequestManager) {
 func (prm *pauseRequestMessage) pause(rm *RequestManager) error {
 	inProgressRequestStatus, ok := rm.inProgressRequestStatuses[prm.id]
 	if !ok {
-		return errors.New("request not found")
+		return graphsync.RequestNotFoundErr{}
 	}
 	if inProgressRequestStatus.paused {
 		return errors.New("request is already paused")