diff --git a/loopy/codegen/instruction.py b/loopy/codegen/instruction.py
index fe7124fdd2a1a0054f6bf4780ac55fd80e93737f..06803f76ed5fa6378930d8afaf1ba869ea83e8f7 100644
--- a/loopy/codegen/instruction.py
+++ b/loopy/codegen/instruction.py
@@ -93,6 +93,9 @@ def generate_expr_instruction_code(kernel, insn, codegen_state):
     from loopy.expression import dtype_to_type_context, VectorizabilityChecker
 
     if codegen_state.vectorization_info:
+        if insn.atomicity:
+            raise Unvectorizable("atomic operation")
+
         vinfo = codegen_state.vectorization_info
         vcheck = VectorizabilityChecker(
                 kernel, vinfo.iname, vinfo.length)