diff --git a/CMakeLists.txt b/CMakeLists.txt
index bd60733..6114285 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,8 +22,8 @@ target_link_libraries(simple-web-server INTERFACE ${CMAKE_THREAD_LIBS_INIT})
 # Remove Boost system, thread, regex components; use Boost::<component> aliases; remove Boost target_include_directories
 if(USE_STANDALONE_ASIO)
     target_compile_definitions(simple-web-server INTERFACE USE_STANDALONE_ASIO)
-    find_file(ASIO_HEADER asio.hpp)
-    if(NOT ASIO_HEADER)
+    find_file(HAVE_ASIO asio.hpp)
+    if(NOT HAVE_ASIO)
         message(FATAL_ERROR "Standalone Asio not found")
     endif()
 else()