diff --git a/types/bson/index.d.ts b/types/bson/index.d.ts
index b1f622ad47..67df319bf6 100644
--- a/types/bson/index.d.ts
+++ b/types/bson/index.d.ts
@@ -1,4 +1,4 @@
-// Type definitions for bson 1.0
+// Type definitions for bson 1.0.4
 // Project: https://github.com/mongodb/js-bson
 // Definitions by: Hiroki Horiuchi <https://github.com/horiuchi/>
 //                 Federico Caselli <https://github.com/CaselIT>
@@ -107,6 +107,14 @@ export class Long {
     toString(radix?: number): string;
     xor(other: Long): Long;
 }
+export class Decimal128 {
+    static fromString(s: string): Decimal128;
+
+    constructor(bytes: Buffer);
+
+    toJSON(): string;
+    toString(): string;
+}
 export class MaxKey {
     constructor();
 }
@@ -135,7 +143,7 @@ export class ObjectID {
     static createFromTime(time: number): ObjectID;
     /**
      * Checks if a value is a valid bson ObjectID
-     * 
+     *
      * @return {boolean} return true if the value is a valid bson ObjectID, return false otherwise.
      */
     static isValid(id: string | number | ObjectID): boolean;
diff --git a/types/mongodb/index.d.ts b/types/mongodb/index.d.ts
index e1837c04ed..6f4f5624e1 100644
--- a/types/mongodb/index.d.ts
+++ b/types/mongodb/index.d.ts
@@ -12,7 +12,7 @@ import { ObjectID } from 'bson';
 import { EventEmitter } from 'events';
 import { Readable, Writable } from "stream";
 
-export { Binary, Double, Long, MaxKey, MinKey, ObjectID, Timestamp } from 'bson';
+export { Binary, Double, Long, Decimal128, MaxKey, MinKey, ObjectID, Timestamp } from 'bson';
 
 // Class documentation : http://mongodb.github.io/node-mongodb-native/2.1/api/MongoClient.html
 export class MongoClient {
diff --git a/types/mongoose/index.d.ts b/types/mongoose/index.d.ts
index 70771c4398..2c58b764d3 100644
--- a/types/mongoose/index.d.ts
+++ b/types/mongoose/index.d.ts
@@ -1307,6 +1307,8 @@ declare module "mongoose" {
     //   the ObjectIdConstructor, so we add the interface below
     interface ObjectId extends mongodb.ObjectID {}
 
+    class Decimal128 extends mongodb.Decimal128 {}
+
     /*
       * section types/embedded.js
       * http://mongoosejs.com/docs/api.html#types-embedded-js
@@ -2019,6 +2021,20 @@ declare module "mongoose" {
         /** This schema type's name, to defend against minifiers that mangle function names. */
         static schemaName: string;
       }
+      /*
+        * section schema/decimal128.js
+        * http://mongoosejs.com/docs/api.html#schema-decimal128-js
+        */
+      class Decimal128 extends SchemaType {
+        /** Decimal128 SchemaType constructor. */
+        constructor(key: string, options?: Object);
+
+        /** Check if the given value satisfies a required validator. */
+        checkRequired(value: any, doc: MongooseDocument): boolean;
+
+        /** This schema type's name, to defend against minifiers that mangle function names. */
+        static schemaName: string;
+      }
 
       /*
         * section schema/mixed.js
diff --git a/types/mongoose/mongoose-tests.ts b/types/mongoose/mongoose-tests.ts
index dc170dccd9..4fb41ef3b2 100644
--- a/types/mongoose/mongoose-tests.ts
+++ b/types/mongoose/mongoose-tests.ts
@@ -61,7 +61,10 @@ mongoose.STATES.hasOwnProperty('');
 mongoose.connection.on('error', cb);
 new mongoose.mongo.MongoError('error').stack;
 mongoose.SchemaTypes.String;
+mongoose.SchemaTypes.ObjectId;
+mongoose.SchemaTypes.Decimal128;
 mongoose.Types.ObjectId;
+mongoose.Types.Decimal128;
 mongoose.version.toLowerCase();
 
 /*
@@ -228,6 +231,7 @@ var schema: mongoose.Schema = new mongoose.Schema({
   age:     { type: Number, min: 18, max: 65 },
   mixed:   mongoose.Schema.Types.Mixed,
   _someId: mongoose.Schema.Types.ObjectId,
+  someDecimal:mongoose.Schema.Types.Decimal128,
   array:      [],
   ofString:   [String],
   ofNumber:   [Number],
@@ -585,6 +589,23 @@ mongooseBuffer.compare(mongooseBuffer);
 /* inherited static properties */
 mongoose.Types.Buffer.from([1, 2, 3]);
 
+/*
+ * section types/decimal128.js
+ * http://mongoosejs.com/docs/api.html#types-decimal128-js
+ */
+var decimal128: mongoose.Types.Decimal128 = mongoose.Types.Decimal128.fromString('123.45678901234567');
+decimal128 = new mongoose.Types.Decimal128(new Buffer('12345'));
+/* practical examples */
+export interface ILargeValuesSchema extends mongoose.MongooseDocument {
+  sum: mongoose.Schema.Types.Decimal128;
+}
+export var LargeValuesSchema = new mongoose.Schema({
+  sum: {
+    type: mongoose.Schema.Types.Decimal128,
+    required: true
+  }
+});
+
 /*
  * section types/objectid.js
  * http://mongoosejs.com/docs/api.html#types-objectid-js
@@ -1050,7 +1071,7 @@ aggregate.unwind(
     includeArrayIndex: "idx",
     preserveNullAndEmptyArrays: true
   });
-  
+
 /*
  * section schematype.js
  * http://mongoosejs.com/docs/api.html#schematype-js