diff --git a/types/node/index.d.ts b/types/node/index.d.ts
index f132b2e64f..74ad1f4b32 100644
--- a/types/node/index.d.ts
+++ b/types/node/index.d.ts
@@ -2490,15 +2490,15 @@ declare module "fs" {
     export function futimesSync(fd: number, atime: Date, mtime: Date): void;
     export function fsync(fd: number, callback?: (err?: NodeJS.ErrnoException) => void): void;
     export function fsyncSync(fd: number): void;
-    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
+    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, buffer: Buffer, offset: number, length: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, data: any, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, encoding: string, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
-    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number): number;
-    export function writeSync(fd: number, data: any, position?: number, enconding?: string): number;
-    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
-    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position: number): number;
+    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number | null): number;
+    export function writeSync(fd: number, data: any, position?: number | null, enconding?: string): number;
+    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
+    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position: number | null): number;
     /**
      * Asynchronous readFile - Asynchronously reads the entire contents of a file.
      *
diff --git a/types/node/v0/index.d.ts b/types/node/v0/index.d.ts
index 6e17a4e764..7f6cb0dc0b 100644
--- a/types/node/v0/index.d.ts
+++ b/types/node/v0/index.d.ts
@@ -1274,14 +1274,14 @@ declare module "fs" {
     export function futimesSync(fd: number, atime: Date, mtime: Date): void;
     export function fsync(fd: number, callback?: (err?: NodeJS.ErrnoException) => void): void;
     export function fsyncSync(fd: number): void;
-    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
+    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, buffer: Buffer, offset: number, length: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, data: any, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, encoding: string, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
-    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position: number): number;
-    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
-    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number): number;
+    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position: number | null): number;
+    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
+    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number | null): number;
     /**
      * Asynchronous readFile - Asynchronously reads the entire contents of a file.
      *
diff --git a/types/node/v4/index.d.ts b/types/node/v4/index.d.ts
index deb4cdea37..febe265a41 100644
--- a/types/node/v4/index.d.ts
+++ b/types/node/v4/index.d.ts
@@ -1603,15 +1603,15 @@ declare module "fs" {
     export function futimesSync(fd: number, atime: Date, mtime: Date): void;
     export function fsync(fd: number, callback?: (err?: NodeJS.ErrnoException) => void): void;
     export function fsyncSync(fd: number): void;
-    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
+    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, buffer: Buffer, offset: number, length: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, data: any, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, encoding: string, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
-    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number): number;
-    export function writeSync(fd: number, data: any, position?: number, enconding?: string): number;
-    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
-    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number): number;
+    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number | null): number;
+    export function writeSync(fd: number, data: any, position?: number | null, enconding?: string): number;
+    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
+    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number | null): number;
     /**
      * Asynchronous readFile - Asynchronously reads the entire contents of a file.
      *
diff --git a/types/node/v6/index.d.ts b/types/node/v6/index.d.ts
index f18f006e0c..ebd6357026 100644
--- a/types/node/v6/index.d.ts
+++ b/types/node/v6/index.d.ts
@@ -2401,15 +2401,15 @@ declare module "fs" {
     export function futimesSync(fd: number, atime: Date, mtime: Date): void;
     export function fsync(fd: number, callback?: (err?: NodeJS.ErrnoException) => void): void;
     export function fsyncSync(fd: number): void;
-    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
+    export function write(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, buffer: Buffer, offset: number, length: number, callback?: (err: NodeJS.ErrnoException, written: number, buffer: Buffer) => void): void;
     export function write(fd: number, data: any, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
     export function write(fd: number, data: any, offset: number, encoding: string, callback?: (err: NodeJS.ErrnoException, written: number, str: string) => void): void;
-    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number): number;
-    export function writeSync(fd: number, data: any, position?: number, enconding?: string): number;
-    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
-    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position: number): number;
+    export function writeSync(fd: number, buffer: Buffer, offset: number, length: number, position?: number | null): number;
+    export function writeSync(fd: number, data: any, position?: number | null, enconding?: string): number;
+    export function read(fd: number, buffer: Buffer, offset: number, length: number, position: number | null, callback?: (err: NodeJS.ErrnoException, bytesRead: number, buffer: Buffer) => void): void;
+    export function readSync(fd: number, buffer: Buffer, offset: number, length: number, position: number | null): number;
     /**
      * Asynchronous readFile - Asynchronously reads the entire contents of a file.
      *