diff --git a/protobufjs/protobufjs.d.ts b/protobufjs/protobufjs.d.ts
index 55d2bea66e..7133df6f69 100644
--- a/protobufjs/protobufjs.d.ts
+++ b/protobufjs/protobufjs.d.ts
@@ -11,6 +11,7 @@ declare module ProtoBuf {
     
     var Builder: Builder;
     var ByteBuffer: Buffer;
+    var Long: LongStatic;
     var DotProto: DotProto;
     var Reflect: Reflect;
 
@@ -33,6 +34,69 @@ declare module ProtoBuf {
     
     export function newBuilder(options?: {[key: string]: any}): ProtoBuilder;
   
+    export interface LongStatic {
+      new(low?: number, high?: number, unsigned?:boolean): Long;
+
+      MAX_UNSIGNED_VALUE: Long;
+      MAX_VALUE: Long;
+      MIN_VALUE: Long;
+      NEG_ONE: Long;
+      ONE: Long;
+      UONE: Long;
+      UZERO: Long;
+      ZERO: Long;
+
+      fromBits(lowBits: number, highBits: number, unsigned?: boolean): Long;
+      fromInt(value: number, unsigned?: boolean): Long;
+      fromNumber(value: number, unsigned?: boolean): Long;
+      fromString(str: string, unsigned?: boolean | number, radix?: number): Long;
+      fromValue(val: Long | number | string): Long;
+
+      isLong(obj: any): boolean;
+    }
+
+    // Based on https://github.com/dcodeIO/Long.js and https://github.com/borisyankov/DefinitelyTyped/blob/master/long/long.d.ts
+    export interface Long {
+      high: number;
+      low: number;
+      unsigned :boolean;
+
+      add(other: Long | number | string): Long;
+      and(other: Long | number | string): Long;
+      compare(other: Long | number | string): number;
+      div(divisor: Long | number | string): Long;
+      equals(other: Long | number | string): boolean;
+      getHighBits(): number;
+      getHighBitsUnsigned(): number;
+      getLowBits(): number;
+      getLowBitsUnsigned(): number;
+      getNumBitsAbs(): number;
+      greaterThan(other: Long | number | string): boolean;
+      greaterThanOrEqual(other: Long | number | string): boolean;
+      isEven(): boolean;
+      isNegative(): boolean;
+      isOdd(): boolean;
+      isPositive(): boolean;
+      isZero(): boolean;
+      lessThan(other: Long | number | string): boolean;
+      lessThanOrEqual(other: Long | number | string): boolean;
+      modulo(divisor: Long | number | string): Long;
+      multiply(multiplier: Long | number | string): Long;
+      negate(): Long;
+      not(): Long;
+      notEquals(other: Long | number | string): boolean;
+      or(other: Long | number | string): Long;
+      shiftLeft(numBits: number | Long): Long;
+      shiftRight(numBits: number | Long): Long;
+      shiftRightUnsigned(numBits: number | Long): Long;
+      subtract(other: Long | number | string): Long;
+      toInt(): number;
+      toNumber(): number;
+      toSigned(): Long;
+      toString(radix?: number): string;
+      toUnsigned(): Long;
+      xor(other: Long | number | string): Long;
+    }
     
     // ==========
     // protobufjs/src/ProtoBuf/Builder.js