Background: Feline mastitis is an uncommon inflammation of mammary gland that is caused by bacterial infection of lactating gland or during pseudopregnancy. Milk accumulation may cause acute septic mastitis due to congestion of milk. It is believed that the microorganisms gain entrance via fissures in the nipples and adjacent skin or spread by way of both the ducts and the lymphatics. The staphylococci that are a persistent pathogen may cause gangrene within a few days. In cases of mastitis that does not respond medical treatment, radical treatment is mastectomy.