A review is made of 62 cases with the diagnosis of toxoplasmosis studied in the Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brasil, covering a period of 10 years (1958-1968), with 8 cases only of probable acquired toxoplasmosis of the nervous system. These 8 patients gave a basis for a clinical, laboratorial and therapeutic study. It was emphasized that it is almost impossible to make a definite diagnosis of acquired toxoplasmosis of the nervous system because there are no specific signs and symptoms. On the other hand, the parasite itself is difficult to demonstrate in a purely neurological disease, because it is seldom found in the cerebrospinal fluid and a brain biopsy is not a common procedure. The approximative diagnosis in the cases here reported was based on the clinical picture in association with several laboratory findings, specially a positive high antibody titer of the dye-test or a Sabin-Feldman test above 1:100 and/or an ondulating course; the results of specific treatment were also considered. In all cases the dye-test was made in serum but only in two cases it was made in the cerebrospinal fluid. The serum reactions were repeated in 5 cases and the immunofluorescent test was realized in one patient only. The clinical features, laboratory findings, therapeutic methods and results were discussed.