diff --git a/index.js b/index.js
index 576e334..59d5be3 100644
--- a/index.js
+++ b/index.js
@@ -2,7 +2,8 @@
 
 const fs = require('fs');
 const util = require('util');
-const find = require('findup-sync');
+const find = require('find-git-root');
+const path = require('path');
 const readFile = util.promisify(fs.readFile);
 
 function branch(cwd, callback) {
@@ -31,9 +32,10 @@ function parseBranch(buf) {
 }
 
 function gitHeadPath(cwd) {
-  const filepath = find('.git/HEAD', { cwd: cwd || process.cwd() });
+  cwd = cwd || process.cwd();
+  const filepath = path.join(find(cwd), 'HEAD');
   if (!fs.existsSync(filepath)) {
-    throw new Error('.git/HEAD does not exist');
+    throw new Error(`${path.relative(cwd, filepath)} does not exist`);
   }
   return filepath;
 }
diff --git a/package.json b/package.json
index 1a3724d..fd72724 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
     "test": "mocha"
   },
   "dependencies": {
-    "findup-sync": "^2.0.0"
+    "find-git-root": "^1.0.4"
   },
   "devDependencies": {
     "gfc": "^2.0.1",
diff --git a/test/test.js b/test/test.js
index ff4518a..bf04550 100644
--- a/test/test.js
+++ b/test/test.js
@@ -1,18 +1,30 @@
 'use strict';
 
+const cp = require('child_process');
 const gfc = require('gfc');
 const path = require('path');
 const util = require('util');
 const assert = require('assert');
 const rimraf = util.promisify(require('rimraf'));
 const branch = require('..');
-const fixtures = path.join(__dirname, 'fixtures');
+const fixturesBase = path.join(__dirname, 'fixtures');
+const fixtures = path.join(fixturesBase, 'git');
+const worktreeFixtures = path.join(fixturesBase, 'worktree');
+
+const exec = util.promisify(cp.exec);
+const createWorktree = async(gitDir) => exec(['git', 'worktree', 'add', '-b', 'some-branch', worktreeFixtures].join(' '), { cwd: gitDir });
+
+const create = async() => {
+  await rimraf(fixturesBase);
+  await gfc(fixtures);
+  await createWorktree(fixtures);
+};
+
 
-const create = async() => await rimraf(fixtures).then(() => gfc(fixtures));
 
 describe('git-branch', function() {
   beforeEach(() => create());
-  afterEach(() => rimraf(fixtures));
+  afterEach(() => rimraf(fixturesBase));
 
   it('should get branch (sync)', () => assert.equal(branch.sync(fixtures), 'master'));
   it('should get branch (promise)', function() {
@@ -25,4 +37,5 @@ describe('git-branch', function() {
       cb();
     });
   });
+  it('should work with a git worktree', () => assert.strictEqual(branch.sync(worktreeFixtures), 'some-branch'));
 });