Abstract Four hundred ninety-six patients with bronchogenic carcinoma were divided into comparable groups and each treated for three months with nitrogen mustard, diethylstilbestrol, testosterone propionate, cortisone, progesterone or an inert compound (lactose). Sixty-three per cent of the patients given nitrogen mustard were alive at the end of ninety days as compared to 51 per cent of the patients receiving the inert compound and 37 per cent of the patients treated with cortisone. The first course of nitrogen mustard improved the survival rate at the thirtieth day only. The second course of the drug failed to exert any further effect on survival. Mortality in the group treated with cortisone was highest during the second month of treatment. No explanation could be found for the apparent deleterious effects of cortisone. The median survival time for the control group was ninety-three days as compared to 121 days for the group receiving nitrogen mustard and fifty-six days for the patients given cortisone. The estimated mean survival time also confirmed the very slight advantage of nitrogen mustard as compared to the inert compound as well as demonstrating the accelerated death rate among the patients given cortisone. The results with the other drugs were intermediate between those with the inert compound and cortisone, the experience in the group receiving progesterone being almost as bad as that in the group given cortisone. Thirteen patients died of exsanguinating hemorrhage; six had received diethylstilbestrol and five had keratinizing squamous carcinoma as compared to an over-all incidence of 6 per cent of this type of bronchogenic carcinoma in this series.