diff --git a/index.js b/index.js
index bdea604..cfb0660 100644
--- a/index.js
+++ b/index.js
@@ -712,7 +712,7 @@ function bidirectionalIndexOf (buffer, val, byteOffset, encoding, dir) {
   // Normalize byteOffset
   if (typeof byteOffset === 'string') {
     encoding = byteOffset
-    byteOffset = 0
+    byteOffset = undefined
   } else if (byteOffset > 0x7fffffff) {
     byteOffset = 0x7fffffff
   } else if (byteOffset < -0x80000000) {
diff --git a/test/methods.js b/test/methods.js
index b1bf75b..51b3fd6 100644
--- a/test/methods.js
+++ b/test/methods.js
@@ -138,3 +138,12 @@ test('buffer.slice out of range', function (t) {
   t.equal((new B('hallo')).slice(10, 2).toString(), '')
   t.end()
 })
+
+test('lastIndexOf with encoding as second arg', function (t) {
+  const b = new B('abcdefghij')
+  t.equal(b.lastIndexOf('b'), 1)
+  t.equal(b.lastIndexOf('b', 'utf8'), 1)
+  t.equal(b.lastIndexOf('b', 'latin1'), 1)
+  t.equal(b.lastIndexOf('b', 'binary'), 1)
+  t.end()
+})