diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 08b5ff4..21727ce 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -321,11 +321,11 @@
                $<INSTALL_INTERFACE:include/>
         PRIVATE ${MBEDTLS_DIR}/library/)
     # Pass-through MBEDTLS_CONFIG_FILE and MBEDTLS_USER_CONFIG_FILE
-    if(DEFINED MBEDTLS_CONFIG_FILE)
+    if(MBEDTLS_CONFIG_FILE)
         target_compile_definitions(${target}
             PUBLIC MBEDTLS_CONFIG_FILE="${MBEDTLS_CONFIG_FILE}")
     endif()
-    if(DEFINED MBEDTLS_USER_CONFIG_FILE)
+    if(MBEDTLS_USER_CONFIG_FILE)
         target_compile_definitions(${target}
             PUBLIC MBEDTLS_USER_CONFIG_FILE="${MBEDTLS_USER_CONFIG_FILE}")
     endif()