A phase III study was designed comparing the effectiveness of Hexamethylmelamine (NSC 13875) to Dibromodulcitol (NSC 104800) in lung carcinoma. 250 of the 316 patients entered on the study were stratified into groups according to stage of disease and cell type. The results showed Hexamethylmelamine to be more effective in patients with squamous cell carcinoma and slightly superior to Dibromodulcitol in patients with anaplastic/undifferentiated cell carcinoma, whereas Dibromodulcitol proved to be more effective in patients with adenocarcinoma.