diff --git a/lib/script/script.js b/lib/script/script.js
index a8cb52e6..3aedf8c2 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -1397,8 +1397,8 @@ Script.prototype.indexOf = function indexOf(data) {
 };
 
 /**
- * Test a script to see if it is valid
- * script code (no non-existent opcodes).
+ * Test a script to see if it is likely
+ * to be script code (no weird opcodes).
  * @returns {Boolean}
  */
 
@@ -1407,7 +1407,22 @@ Script.prototype.isCode = function isCode() {
     if (op.value === -1)
       return false;
 
-    if (op.value > opcodes.OP_NOP10)
+    if (op.isDisabled())
+      return false;
+
+    switch (op.value) {
+      case opcodes.OP_RESERVED:
+      case opcodes.OP_NOP:
+      case opcodes.OP_VER:
+      case opcodes.OP_VERIF:
+      case opcodes.OP_VERNOTIF:
+      case opcodes.OP_RESERVED1:
+      case opcodes.OP_RESERVED2:
+      case opcodes.OP_NOP1:
+        return false;
+    }
+
+    if (op.value > opcodes.OP_NOP3)
       return false;
   }