Knowledgebase
How to display out of stock products on the frontend in Magento
The default setting in Magento is to not display products on the store's frontend if they are out of stock.
If you want to display out of stock products on the frontend of your Magento store, go to the Magento admin panel > System > Configuration > Inventory (located in the CATALOG section in the left menu). Then click Stock Options and change the Display Out of Stock Products setting to Yes.
Click Save Config to save the change. From now on out of stock products will be displayed on your Magento frontend.