diff --git a/lang/bytecode.c b/lang/bytecode.c
index 6185849..72e93ab 100644
--- a/lang/bytecode.c
+++ b/lang/bytecode.c
@@ -16,15 +16,16 @@
 	OP_GET = 0x06,
 	OP_SET = 0x07,
 	OP_DROP = 0x08,
+	OP_DEPTH_CHECK = 0x09,
 };
 
 // clang-format off
 static const unsigned char bytecode[] = {
-0x05, 0x05, 0x05, 0x01, 0x6a, 0x02, 0x00, 0x00, 0x07, 0x01,
-0x05, 0x06, 0x01, 0x06, 0x01, 0x04, 0x02, 0x41, 0x64, 0x64,
-0x00, 0x07, 0x02, 0x05, 0x01, 0x02, 0x00, 0x00, 0x00, 0x06,
-0x02, 0x04, 0x02, 0x4d, 0x69, 0x6e, 0x75, 0x73, 0x00, 0x07,
-0x03, 0x06, 0x03, 0x07, 0x00, 0x08, 0x03, 0x03,
+0x09, 0x01, 0x05, 0x05, 0x05, 0x01, 0x6a, 0x02, 0x00, 0x00,
+0x07, 0x01, 0x05, 0x06, 0x01, 0x06, 0x01, 0x04, 0x02, 0x41,
+0x64, 0x64, 0x00, 0x07, 0x02, 0x05, 0x01, 0x02, 0x00, 0x00,
+0x00, 0x06, 0x02, 0x04, 0x02, 0x4d, 0x69, 0x6e, 0x75, 0x73,
+0x00, 0x07, 0x03, 0x06, 0x03, 0x07, 0x00, 0x08, 0x03, 0x03,
 };
 // clang-format on
 
@@ -68,6 +69,12 @@
 			vm_stack_drop(state, *pos_code++);
 			break;
 		}
+		case OP_DEPTH_CHECK: {
+			int depth = *pos_code++;
+			abort_if(vm_stack_depth(state) != depth,
+				"stack depth mismatch");
+			break;
+		}
 		default:
 			// Skip over ASCII and unknown OPs
 			break;
diff --git a/lang/compile.py b/lang/compile.py
index fe5efc4..f486d84 100755
--- a/lang/compile.py
+++ b/lang/compile.py
@@ -221,6 +221,13 @@
 	def __repr__(self):
 		return 'IRFunction(name="%s", statements=%s)' % (self.name, self.statements)
 
+class IRDepthCheck():
+	def __init__(self, depth):
+		self.depth = depth
+
+	def __repr__(self):
+		return '\n\tIRDepthCheck(depth=%i)' % (self.depth)
+
 ## IR Generator
 
 def generate_ir_value(value):
@@ -321,6 +328,7 @@
 
 def replace_variables(ir, variables):
 	new_ir = []
+	new_ir.append(IRDepthCheck(1))
 	var_count = len(variables) - 1 # Ignore Return
 	new_ir.append(IRAllocate(var_count))
 	for node in ir:
@@ -386,6 +394,10 @@
 			bytes += b"\x00" # NULL terminator
 		elif isinstance(node, IRReturn):
 			bytes += b"\x03" # OP_RET
+		elif isinstance(node, IRDepthCheck):
+			depth = int(node.depth)
+			bytes += b"\x09" # OP_DEPTH_CHECK
+			bytes += depth.to_bytes(1)
 		else:
 			print("Unknown bytecode node: %s" % (node))
 			return None