diff --git a/lib/manager/npm/extract/monorepo.js b/lib/manager/npm/extract/monorepo.js
index fc3a0e85ba81c2602d7864855d45359f50bbf776..bbe57470a44673538b75c668d1853369f83eb51e 100644
--- a/lib/manager/npm/extract/monorepo.js
+++ b/lib/manager/npm/extract/monorepo.js
@@ -45,7 +45,7 @@ function detectMonorepos(packageFiles) {
         .map(sp => sp.packageJsonName)
         .filter(Boolean);
       // add all names to main package.json
-      packageFile.internalPackages = internalPackages;
+      p.internalPackages = internalPackages;
       for (const subPackage of internalPackageFiles) {
         subPackage.internalPackages = internalPackages.filter(
           name => name !== subPackage.packageJsonName
diff --git a/test/manager/npm/extract/__snapshots__/monorepo.spec.js.snap b/test/manager/npm/extract/__snapshots__/monorepo.spec.js.snap
index 8679dfe9ee8631b1f57ebbd60c9505d87854ef92..9cf490b772f5b7b766e715f58fe7d2d6d96d1877 100644
--- a/test/manager/npm/extract/__snapshots__/monorepo.spec.js.snap
+++ b/test/manager/npm/extract/__snapshots__/monorepo.spec.js.snap
@@ -3,6 +3,10 @@
 exports[`manager/npm/extract .extractPackageFile() uses lerna package settings 1`] = `
 Array [
   Object {
+    "internalPackages": Array [
+      "@org/a",
+      "@org/b",
+    ],
     "lernaDir": ".",
     "lernaPackages": Array [
       "packages/*",
@@ -37,6 +41,10 @@ Array [
 exports[`manager/npm/extract .extractPackageFile() uses yarn workspaces package settings 1`] = `
 Array [
   Object {
+    "internalPackages": Array [
+      "@org/a",
+      "@org/b",
+    ],
     "lernaClient": "yarn",
     "lernaDir": ".",
     "lernaPackages": Array [