diff --git a/CHANGES.rst b/CHANGES.rst
index ef6853c..5eb31e8 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -19,6 +19,9 @@
 
 - The ``py65`` package is no longer a namespace package.
 
+- Fixed assembly and disassembly of 65C02 instruction $64 (``STZ $12``).
+  Patch by Patrick Surry.
+
 1.1.0 (2018-07-01)
 ------------------
 
diff --git a/py65/tests/test_disassembler.py b/py65/tests/test_disassembler.py
index 4175e0c..78e3eff 100644
--- a/py65/tests/test_disassembler.py
+++ b/py65/tests/test_disassembler.py
@@ -536,6 +536,12 @@ class DisassemblerTests(unittest.TestCase):
         self.assertEqual(1, length)
         self.assertEqual('???', disasm)
 
+    def test_disassembles_64_65c02(self):
+        mpu = MPU65C02()
+        length, disasm = self.disassemble([0x64, 0x12], 0x0000, mpu)
+        self.assertEqual(2, length)
+        self.assertEqual('STZ $12', disasm)
+
     def test_disassembles_65(self):
         length, disasm = self.disassemble([0x65, 0x44])
         self.assertEqual(2, length)