Forty two cases of schizophrenic patients were studied. Magnesium was determined in the blood (26 cases) and in the cerebrospinal fluid (11 cases) and sulfur was determined in the blood (22 cases). By statistical treatment of the data obtained the author came to the following conclusions: 1) the variations in the levels of magnesium in the cerebrospinal fluid and of sulfur in the blood are not significative; 2) the levels of blood magnesium are significantly lower in schizophrenic patients in relation to normal values.