diff --git a/types/bson/index.d.ts b/types/bson/index.d.ts
index 3b0feb0113..4d30097478 100644
--- a/types/bson/index.d.ts
+++ b/types/bson/index.d.ts
@@ -182,7 +182,7 @@ export class ObjectID {
      * @param {number} time optional parameter allowing to pass in a second based timestamp.
      * @return {string} return the 12 byte id binary string.
      */
-    generate(time?: number): string;
+    generate(time?: number): Buffer;
     /**
      * Returns the generation date (accurate up to the second) that this ID was generated.
      * @return {date} the generation date