diff --git a/firebase/firebase.d.ts b/firebase/firebase.d.ts
index 9c03d2e769..27e4923a89 100644
--- a/firebase/firebase.d.ts
+++ b/firebase/firebase.d.ts
@@ -10,7 +10,7 @@ interface IFirebaseAuthResult {
 
 interface IFirebaseDataSnapshot {
 	val(): any;
-	child(): IFirebaseDataSnapshot;
+	child(childPath: string): IFirebaseDataSnapshot;
 	forEach(childAction: (childSnapshot: IFirebaseDataSnapshot) => boolean): boolean;
 	hasChild(childPath: string): boolean;
 	hasChildren(): boolean;
@@ -70,4 +70,4 @@ declare class Firebase implements IFirebaseQuery {
 	endAt(priority?: string, name?: string): IFirebaseQuery;
 	endAt(priority?: number, name?: string): IFirebaseQuery;
 	ref(): Firebase;
-}
\ No newline at end of file
+}