diff --git a/psutil/_psutil_osx.c b/psutil/_psutil_osx.c
index 55dd64ca5..ee55f169b 100644
--- a/psutil/_psutil_osx.c
+++ b/psutil/_psutil_osx.c
@@ -1069,8 +1069,8 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
         py_tuple = Py_BuildValue(
             "Iff",
             j + 1,
-            (float)basic_info_th->user_time.microseconds / 1000000.0,
-            (float)basic_info_th->system_time.microseconds / 1000000.0
+            basic_info_th->user_time.seconds + (float)basic_info_th->user_time.microseconds / 1000000.0,
+            basic_info_th->system_time.seconds + (float)basic_info_th->system_time.microseconds / 1000000.0
         );
         if (!py_tuple)
             goto error;