diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index c81cd1c..96cdb45 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -66,6 +66,11 @@
 #error "MBEDTLS_HAVE_TIME_DATE without MBEDTLS_HAVE_TIME does not make sense"
 #endif
 
+#if defined(MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH) && \
+    !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+#error "MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH defined, but not all prerequisites"
+#endif
+
 #if defined(MBEDTLS_CTR_DRBG_C) && !defined(MBEDTLS_AES_C)
 #error "MBEDTLS_CTR_DRBG_C defined, but not all prerequisites"
 #endif