diff --git a/templates/object_apply_service_to_host.conf.erb b/templates/object_apply_service_to_host.conf.erb
index e380810..4de9f85 100644
--- a/templates/object_apply_service_to_host.conf.erb
+++ b/templates/object_apply_service_to_host.conf.erb
@@ -43,7 +43,7 @@ apply Service "<%= @object_servicename %>" to Host {
   max_check_attempts = <%= @max_check_attempts %>
   <%- end -%>
   <%- if @check_period -%>
-  check_period = <%= @check_period %>
+  check_period = "<%= @check_period %>"
   <%- end -%>
   <%- if @check_interval -%>
   check_interval = <%= @check_interval %>