AbstractSix cases of choriocarcinoma, 17 of vesicular mole, 20 normal pregnant females in the first trimester of pregnancy, and 20 normal nonpregnant women with previous normal obstetrical history were evaluated quantitatively for cell‐mediated immunity by response to 2:4 dinitrocholoroben‐zene and recall antigens. Serum immunoglobulins were estimated in all cases. Suppression of cell‐mediated immunity was marked in choriocarcinoma as compared to vesicular mole. Serum IgG levels were significantly diminished in cases of vesicular mole, indicating diminished humoral immunity. Follow‐up after 3 months of treatment with surgery and chemotherapy resulted in marked improvement of cell‐mediated