We performed a retrospective non-random study to evaluate the effectiveness of different therapeutical concepts in the treatment of retinal toxoplasmosis. Visual acuity after therapy and at the end of the observation period as well as the recurrence frequency were used to determine the success of treatment. The protocols of 75 patients treated for retinal toxoplasmosis at the University of Hamburg were evaluated for this study. The mean observation period was 220 weeks with a standard deviation of 110 weeks. Concerning the visual outcome, a therapeutic effect was statistically shown for monotherapy with antibiotics and for their combination with corticosteroids. Steroid therapy was demonstrated to be helpful, especially in cases of extramacular localization of fundus lesions. This was probably caused by steroid-induced improvement of vitreous infiltration. As for the different antibiotics used, the combination of clindamycin with sulfmethoxydiazine and/or pyrimethamine showed the best results. Monotherapy with clindamycine alone had statistically no effect on the final visual outcome. The relapse frequency was not influenced by any therapeutic concept used. According to these results, a combination of clindamycine and pyrimethamine should be the therapy of choice for treatment of retinal toxoplasmosis.