diff --git a/lib/targets/web3/generation.ts b/lib/targets/web3/generation.ts
index 0e6347871..75d56e829 100644
--- a/lib/targets/web3/generation.ts
+++ b/lib/targets/web3/generation.ts
@@ -21,11 +21,11 @@ import {
 
 export function codegen(contract: Contract) {
   const template = `
-  import { Contract, ContractOptions, Options } from "web3-eth-contract";
-  import { Block } from "web3-eth";
+  import BN from "bn.js";
+  import { Contract, ContractOptions, EventOptions } from "web3-eth-contract";
   import { EventLog } from "web3-core";
   import { EventEmitter } from "events";
-  import { Callback, TransactionObject } from "./types";
+  import { Callback, TransactionObject, ContractEvent } from "./types";
 
   export class ${contract.name} extends Contract {
     constructor(jsonInterface: any[], address?: string, options?: ContractOptions);
@@ -37,11 +37,7 @@ export function codegen(contract: Contract) {
     events: {
       ${contract.events.map(generateEvents).join("\n")}
       allEvents: (
-          options?: {
-              filter?: object;
-              fromBlock?: number | string;
-              topics?: (null|string)[];
-          },
+          options?: EventOptions,
           cb?: Callback<EventLog>
       ) => EventEmitter;
     };
@@ -86,15 +82,7 @@ function generateOutputTypes(outputs: Array<AbiParameter>): string {
 }
 
 function generateEvents(event: EventDeclaration) {
-  return `
-  ${event.name}(
-    options?: {
-        filter?: object;
-        fromBlock?: number | string;
-        topics?: (null|string)[];
-    },
-    cb?: Callback<EventLog>): EventEmitter;
-  `;
+  return `${event.name}: ContractEvent<${generateOutputTypes(event.inputs)}>`;
 }
 
 function generateInputType(evmType: EvmType): string {
@@ -124,9 +112,9 @@ function generateInputType(evmType: EvmType): string {
 function generateOutputType(evmType: EvmType): string {
   switch (evmType.constructor) {
     case IntegerType:
-      return "string";
+      return "BN";
     case UnsignedIntegerType:
-      return "string";
+      return "BN";
     case AddressType:
       return "string";
     case VoidType:
diff --git a/lib/targets/web3/index.ts b/lib/targets/web3/index.ts
index 0656e2329..7f55c8bf9 100644
--- a/lib/targets/web3/index.ts
+++ b/lib/targets/web3/index.ts
@@ -1,4 +1,3 @@
-import { Contract } from "../../parser/abiParser";
 import { TsGeneratorPlugin, TContext, TFileDesc } from "ts-generator";
 import { join } from "path";
 import { extractAbi, parse } from "../../parser/abiParser";
@@ -46,17 +45,31 @@ export class Web3 extends TsGeneratorPlugin {
       {
         path: join(this.outDirAbs, "types.d.ts"),
         contents: `
-  import { Transaction } from "web3-core";
+  import { EventLog } from "web3-core";
+  import BN from "bn.js";
+  import { EstimateGasOptions, EventOptions } from "web3-eth-contract";
+  import { EventEmitter } from "events";
   // @ts-ignore
   import PromiEvent from "web3-core-promievent";
   export type Callback<T> = (error: Error, result: T) => void;
   export interface TransactionObject<T> {
     arguments: any[];
-    call(tx?: Transaction): Promise<T>;
-    send(tx?: Transaction): PromiEvent<T>;
-    estimateGas(tx?: Transaction): Promise<number>;
+    call(options?: EstimateGasOptions): Promise<T>;
+    send(options?: EstimateGasOptions): PromiEvent<T>;
+    estimateGas(options?: EstimateGasOptions): Promise<number>;
     encodeABI(): string;
-  }`,
+  }
+  export interface ContractEventLog<T> extends EventLog {
+    returnValues: T;
+  }
+  export interface ContractEventEmitter<T> extends EventEmitter {
+    on(event: 'data' | 'changed', listener: (event: ContractEventLog<T>) => void): this;
+    on(event: 'error', listener: (error: Error) => void): this;
+  }
+  export type ContractEvent<T> = (
+    options?: EventOptions,
+    cb?: Callback<ContractEventLog<T>>
+  ) => ContractEventEmitter<T>;`,
       },
     ];
   }