diff --git a/gitignore.js b/gitignore.js
index 3feaad6..6a1a57a 100644
--- a/gitignore.js
+++ b/gitignore.js
@@ -44,6 +44,7 @@ const reduceIgnore = files => {
 };
 
 const ensureAbsolutePathForCwd = (cwd, p) => {
+	cwd = slash(cwd);
 	if (path.isAbsolute(p)) {
 		if (p.startsWith(cwd)) {
 			return p;
diff --git a/gitignore.test.js b/gitignore.test.js
index eb02221..72ae0f2 100644
--- a/gitignore.test.js
+++ b/gitignore.test.js
@@ -1,5 +1,6 @@
 import path from 'path';
 import test from 'ava';
+import slash from 'slash';
 import gitignore from './gitignore';
 
 test('gitignore', async t => {
@@ -10,6 +11,12 @@ test('gitignore', async t => {
 	t.deepEqual(actual, expected);
 });
 
+test('gitignore - mixed path styles', async t => {
+	const cwd = path.join(__dirname, 'fixtures/gitignore');
+	const isIgnored = await gitignore({cwd});
+	t.true(isIgnored(slash(path.resolve(cwd, 'foo.js'))));
+});
+
 test('gitignore - sync', t => {
 	const cwd = path.join(__dirname, 'fixtures/gitignore');
 	const isIgnored = gitignore.sync({cwd});