diff --git a/cmake/cares.cmake b/cmake/cares.cmake
index 4ea0d8725d0..c09f6940c91 100644
--- a/cmake/cares.cmake
+++ b/cmake/cares.cmake
@@ -22,7 +22,7 @@ if("${gRPC_CARES_PROVIDER}" STREQUAL "module")
     # See https://github.com/grpc/grpc/issues/17255
     set(HAVE_LIBNSL OFF CACHE BOOL "avoid cares dependency on libnsl")
   endif()
-  add_subdirectory(third_party/cares/cares)
+  add_subdirectory("${CARES_ROOT_DIR}" third_party/cares/cares)
 
   if(TARGET c-ares)
     set(_gRPC_CARES_LIBRARIES c-ares)