We evaluated the effects of the addition of corticosteroids to antibiotic therapy in the treatment of staphylococcal endophthalmitis in rabbits. Twenty-four hours after the induction of infection with Staphylococcus aureus, penicillin G, penicillin G and dexamethasone or prednisolone, or saline was injected retrobulbarly for ten days. Afterward, there was no ophthalmoscopic difference between the penicillin and corticosteroid-treated group and those animals receiving only penicillin G. At day 60, however, the fundus was visible in 64% of eyes treated with penicillin G with corticosteroids in contrast to 39% of those eyes treated only with penicillin G (P less than .025). The results between dexamethasone and prednisolone use were not significant. Retrobulbar corticosteroids in combination with effective antibiotic therapy effectively treated experimental bacterial endophthalmitis.