Toxoplasmosis is the most frequent parasitic infection of the CNS in the immunocompromised host. When promptly treated with the sulfadiazine-pyrimethamine combination patients with cerebral toxoplasmosis characteristically respond with clear clinical and CT improvement within 1-2 weeks. We report the results achieved with the combination sulfamethoxazole-trimethoprim, and conclude that both combinations have similar effects in the treatment of CNS toxoplasmosis.