diff --git a/packages/pnpm/src/requirePnpmfile.ts b/packages/pnpm/src/requirePnpmfile.ts
index f008d7b3a9..de2dbe1b37 100644
--- a/packages/pnpm/src/requirePnpmfile.ts
+++ b/packages/pnpm/src/requirePnpmfile.ts
@@ -1,4 +1,5 @@
 import logger from '@pnpm/logger'
+import { PackageJson } from '@pnpm/types'
 import chalk from 'chalk'
 import fs = require('fs')
 
@@ -14,8 +15,12 @@ export default (pnpmFilePath: string, prefix: string) => {
     }
     if (pnpmfile && pnpmfile.hooks && pnpmfile.hooks.readPackage) {
       const readPackage = pnpmfile.hooks.readPackage
-      pnpmfile.hooks.readPackage = function (...args: any[]) { // tslint:disable-line
-        const newPkg = readPackage(...args)
+      pnpmfile.hooks.readPackage = function (pkg: PackageJson, ...args: any[]) { // tslint:disable-line
+        pkg.dependencies = pkg.dependencies || {}
+        pkg.devDependencies = pkg.devDependencies || {}
+        pkg.optionalDependencies = pkg.optionalDependencies || {}
+        pkg.peerDependencies = pkg.peerDependencies || {}
+        const newPkg = readPackage(pkg, ...args)
         if (!newPkg) {
           const err = new Error(`readPackage hook did not return a package manifest object. Hook imported via ${pnpmFilePath}`)
            // tslint:disable:no-string-literal
diff --git a/packages/pnpm/test/install/hooks.ts b/packages/pnpm/test/install/hooks.ts
index c0835494bc..60709a4ac2 100644
--- a/packages/pnpm/test/install/hooks.ts
+++ b/packages/pnpm/test/install/hooks.ts
@@ -10,6 +10,7 @@ import {
 } from '../utils'
 
 const test = promisifyTape(tape)
+const testOnly = promisifyTape(tape.only)
 
 test('readPackage hook', async (t: tape.Test) => {
   const project = prepare(t)
@@ -378,3 +379,28 @@ test('pnpmfile: run afterAllResolved hook', async (t: tape.Test) => {
   t.equal(hookLog.hook, 'afterAllResolved', 'logged hook name')
   t.equal(hookLog.message, 'All resolved', 'logged the message')
 })
+
+test('readPackage hook normalizes the package manifest', async (t: tape.Test) => {
+  const project = prepare(t)
+
+  await fs.writeFile('pnpmfile.js', `
+    'use strict'
+    module.exports = {
+      hooks: {
+        readPackage (pkg) {
+          if (pkg.name === 'dep-of-pkg-with-1-dep') {
+            pkg.dependencies['is-positive'] = '*'
+            pkg.optionalDependencies['is-negative'] = '*'
+            pkg.peerDependencies['is-negative'] = '*'
+            pkg.devDependencies['is-positive'] = '*'
+          }
+          return pkg
+        }
+      }
+    }
+  `, 'utf8')
+
+  await execPnpm('install', 'dep-of-pkg-with-1-dep')
+
+  t.pass('code in pnpmfile did not fail')
+})