Haptoglobin and transferrin types were studied in schizophrenic patients and controls. In the haptoglobin system a significant departure from the Hardy-Wein-berg equilibrium with an excess of heterozygotes was found among the patients (p& < 0.01). The distribution of haptoglobin types in the schizophrenic patients was significantly different from that in the controls. The distribution of transferrin types showed a good agreement with the Hardy-Weinberg equilibrium. There was no significant difference between patients and controls with respect to transferrin types.