diff --git a/office_hours.theme.inc b/office_hours.theme.inc
index 3380307..64301b5 100644
--- a/office_hours.theme.inc
+++ b/office_hours.theme.inc
@@ -127,6 +127,7 @@ function theme_office_hours_field_formatter_default($vars) {
       break;
   }
 
+  $html = str_replace(array('am','pm'), array('a.m.','p.m.'), $html);
   return $html;
 }