Seventeen patients with active toxoplasmic retinochoroiditis were treated for four weeks, seven with clindamycin alone and ten with a combination of clindamycin and sulfadiazine. The follow-up period ranged from six months to four years. Results of the Sabin-Feldman dye test were positive in all patients. Five of the seven patients treated with clindamycin alone showed improvement two weeks after treatment was begun, while eight of the ten patients treated with combined clindamycin and sulfadiazine showed both subjective and objective improvement within ten days and signs of healing within three weeks. Since clindamycin and sulfadiazine operate on unrelated metabolic pathways of Toxoplasma, they may act synergistically. A regimen consisting of this combination may be appropriate for the treatment of ocular toxoplasmosis.