diff --git a/helper.go b/helper.go
index ac79668..08da786 100644
--- a/helper.go
+++ b/helper.go
@@ -111,6 +111,27 @@ func stringToObjectID(object map[string]interface{}) error {
 	return nil
 }
 
+// sliceToObjectID converts _id key from slice of strings to slice of bson.ObjectId
+func sliceToObjectID(object map[string]interface{}) error {
+	if id, ok := object["id"]; ok {
+		delete(object, "id")
+		ids := strings.Split(id.(string), ",")
+		bsonIds := []bson.ObjectId{}
+		for _, id := range ids {
+			if !bson.IsObjectIdHex(id) {
+				return ErrInvalidInput("id is a invalid hex representation of an ObjectId")
+			}
+
+			if reflect.TypeOf(id).String() != "bson.ObjectId" {
+				bsonIds = append(bsonIds, bson.ObjectIdHex(id))
+			}
+		}
+		object["_id"] = bsonIds
+	}
+
+	return nil
+}
+
 // IsConditionalCheckErr check if err is dynamoDB condition error
 func IsConditionalCheckErr(err error) bool {
 	if ae, ok := err.(awserr.RequestFailure); ok {
diff --git a/mongodb.go b/mongodb.go
index d937367..b9e4194 100644
--- a/mongodb.go
+++ b/mongodb.go
@@ -218,8 +218,17 @@ func (s *MongoSession) GetAll(filter Filter, resultsTypeHint interface{}, order
 	slicePointer.Elem().Set(results)
 
 	if !s.repoDef.IsCustomID() {
-		if err := stringToObjectID(filter); err != nil {
-			return nil, ErrInvalidInput(err)
+		if id, ok := filter["id"]; ok {
+			// check if id field contains values separated by comma
+			if ok := strings.Contains(id.(string), ","); ok {
+				if err := sliceToObjectID(filter); err != nil {
+					return nil, ErrInvalidInput(err)
+				}
+			} else {
+				if err := stringToObjectID(filter); err != nil {
+					return nil, ErrInvalidInput(err)
+				}
+			}
 		}
 	}
 
@@ -417,6 +426,24 @@ func toMongoFilter(filter Filter) (map[string]interface{}, error) {
 			}
 			return nil, fmt.Errorf("unknown filter specification - supported type is $pattern")
 		}
+		// if filter key contains multiple values to search by
+		if val, ok := value.(string); ok {
+			if values := strings.Split(val, ","); len(values) > 1 {
+				mgf[key] = bson.M{
+					"$in": values,
+				}
+				continue
+			}
+		}
+		// if filter _id contains multiple id to search by
+		if val, ok := value.([]bson.ObjectId); ok {
+			if len(val) > 1 {
+				mgf[key] = bson.M{
+					"$in": val,
+				}
+				continue
+			}
+		}
 		mgf[key] = value // copy over the key=>value pairs to do exact matching
 	}
 	return mgf, nil