diff --git a/.changeset/rare-carrots-sleep.md b/.changeset/rare-carrots-sleep.md
new file mode 100644
index 0000000000..508c7276a2
--- /dev/null
+++ b/.changeset/rare-carrots-sleep.md
@@ -0,0 +1,5 @@
+---
+"@pnpm/npm-resolver": patch
+---
+
+Avoid conflicts in metadata, when a package name has upper case letters.
diff --git a/packages/npm-resolver/src/pickPackage.ts b/packages/npm-resolver/src/pickPackage.ts
index 04c3e2c9ed..2954cba9af 100644
--- a/packages/npm-resolver/src/pickPackage.ts
+++ b/packages/npm-resolver/src/pickPackage.ts
@@ -1,3 +1,4 @@
+import crypto from 'crypto'
 import { promises as fs } from 'fs'
 import path from 'path'
 import PnpmError from '@pnpm/error'
@@ -76,7 +77,7 @@ export default async (
   }
 
   const registryName = getRegistryName(opts.registry)
-  const pkgMirror = path.join(ctx.storeDir, ctx.metaDir, registryName, `${spec.name}.json`)
+  const pkgMirror = path.join(ctx.storeDir, ctx.metaDir, registryName, `${encodePkgName(spec.name)}.json`)
   const limit = metafileOperationLimits[pkgMirror] = metafileOperationLimits[pkgMirror] || pLimit(1)
 
   let metaCachedInStore: PackageMeta | null | undefined
@@ -146,6 +147,13 @@ export default async (
   }
 }
 
+function encodePkgName (pkgName: string) {
+  if (pkgName !== pkgName.toLowerCase()) {
+    return `${pkgName}_${crypto.createHash('md5').update(pkgName).digest('hex')}`
+  }
+  return pkgName
+}
+
 async function loadMeta (pkgMirror: string): Promise<PackageMeta | null> {
   try {
     return await loadJsonFile<PackageMeta>(pkgMirror)
diff --git a/packages/npm-resolver/test/index.ts b/packages/npm-resolver/test/index.ts
index a72d8f353a..994823c171 100644
--- a/packages/npm-resolver/test/index.ts
+++ b/packages/npm-resolver/test/index.ts
@@ -17,6 +17,7 @@ const isPositiveMetaWithDeprecated = loadJsonFile.sync<any>(path.join(__dirname,
 const isPositiveMetaFull = loadJsonFile.sync<any>(path.join(__dirname, 'meta', 'is-positive-full.json'))
 const isPositiveBrokenMeta = loadJsonFile.sync<any>(path.join(__dirname, 'meta', 'is-positive-broken.json'))
 const sindresorhusIsMeta = loadJsonFile.sync<any>(path.join(__dirname, 'meta', 'sindresorhus-is.json'))
+const jsonMeta = loadJsonFile.sync<any>(path.join(__dirname, 'meta', 'JSON.json'))
 /* eslint-enable @typescript-eslint/no-explicit-any */
 
 const registry = 'https://registry.npmjs.org/'
@@ -73,6 +74,30 @@ test('resolveFromNpm()', async () => {
   expect(meta['dist-tags']).toBeTruthy()
 })
 
+test('resolveFromNpm() should save metadata to a unique file when the package name has upper case letters', async () => {
+  nock(registry)
+    .get('/JSON')
+    .reply(200, jsonMeta)
+
+  const storeDir = tempy.directory()
+  const resolve = createResolveFromNpm({
+    storeDir,
+  })
+  const resolveResult = await resolve({ alias: 'JSON', pref: '1.0.0' }, {
+    registry,
+  })
+
+  expect(resolveResult!.resolvedVia).toBe('npm-registry')
+  expect(resolveResult!.id).toBe('registry.npmjs.org/JSON/1.0.0')
+
+  // The resolve function does not wait for the package meta cache file to be saved
+  // so we must delay for a bit in order to read it
+  const meta = await retryLoadJsonFile<any>(path.join(storeDir, 'metadata/registry.npmjs.org/JSON_0ecd11c1d7a287401d148a23bbd7a2f8.json')) // eslint-disable-line @typescript-eslint/no-explicit-any
+  expect(meta.name).toBeTruthy()
+  expect(meta.versions).toBeTruthy()
+  expect(meta['dist-tags']).toBeTruthy()
+})
+
 test('relative workspace protocol is skipped', async () => {
   const storeDir = tempy.directory()
   const resolve = createResolveFromNpm({
diff --git a/packages/npm-resolver/test/meta/JSON.json b/packages/npm-resolver/test/meta/JSON.json
new file mode 100644
index 0000000000..c8701336e4
--- /dev/null
+++ b/packages/npm-resolver/test/meta/JSON.json
@@ -0,0 +1,90 @@
+{
+  "_id": "JSON",
+  "_rev": "7-cfe2e7994a4dbbf6a471517f1bc1d264",
+  "name": "JSON",
+  "description": "Douglas Crockford's json2.js",
+  "dist-tags": {
+    "latest": "1.0.0"
+  },
+  "versions": {
+    "1.0.0": {
+      "author": {
+        "name": "Douglas Crockford",
+        "email": "douglas@crockford.com",
+        "url": "http://crockford.com"
+      },
+      "contributors": [
+        {
+          "name": "AJ ONeal",
+          "email": "coolaj86@gmail.com",
+          "url": "http://coolaj86.info"
+        }
+      ],
+      "name": "JSON",
+      "description": "Douglas Crockford's json2.js",
+      "keywords": [
+        "ender"
+      ],
+      "version": "1.0.0",
+      "homepage": "http://json.org",
+      "repository": {
+        "url": "git://github.com/douglascrockford/JSON-js.git"
+      },
+      "main": "json2.js",
+      "engines": {
+        "node": ">= 0.2.0"
+      },
+      "dependencies": {},
+      "devDependencies": {},
+      "_npmJsonOpts": {
+        "file": "/Users/coolaj86/.npm/JSON/1.0.0/package/package.json",
+        "wscript": false,
+        "contributors": false,
+        "serverjs": false
+      },
+      "_id": "JSON@1.0.0",
+      "_engineSupported": true,
+      "_npmVersion": "1.0.22",
+      "_nodeVersion": "v0.4.8",
+      "_defaultsLoaded": true,
+      "dist": {
+        "shasum": "8681531c28f8438a075589ff07248246ea960d8c",
+        "tarball": "https://registry.npmjs.org/JSON/-/JSON-1.0.0.tgz"
+      },
+      "scripts": {},
+      "maintainers": [
+        {
+          "name": "coolaj86",
+          "email": "coolaj86@gmail.com"
+        }
+      ],
+      "directories": {}
+    }
+  },
+  "maintainers": [
+    {
+      "name": "coolaj86",
+      "email": "coolaj86@gmail.com"
+    }
+  ],
+  "time": {
+    "modified": "2018-03-06T01:41:38.380Z",
+    "created": "2011-09-08T00:38:16.426Z",
+    "1.0.0": "2011-09-08T00:38:16.795Z"
+  },
+  "author": {
+    "name": "Douglas Crockford",
+    "email": "douglas@crockford.com",
+    "url": "http://crockford.com"
+  },
+  "repository": {
+    "url": "git://github.com/douglascrockford/JSON-js.git"
+  },
+  "users": {
+    "ukuli": true,
+    "zhnoah": true,
+    "spencermathews": true,
+    "d3ck": true
+  },
+  "_attachments": {}
+}