References in the literature to the frequent occurrence of cervix carcinoma accompanied by nicotine abuse led us to investigate the effects of cigarette smoking on the results of treatment in primary irradiation of cervix carcinoma. As not only nicotine abuse but also diabetes mellitus can lead to angiopathy, we also investigated the influence of diabetes mellitus on the results of treatment. Of 410 nonsmokers with carcinoma of the cervix in Stages I and II, 260 (63.4%) reached the 5-year limit, but only 62 of 115 smokers survived (53.9%). In Stages III and IV there were significantly less favorable rates of cure in patients with nicotine abuse. Of 626 nonsmokers with cervix carcinoma in Stages III and IV, 212 survived (33.9%); but of 153 smokers, only 31 (20.1%) could be cured (P less than 0.01). The frequency of side effects of primary irradiation was distinctly higher in smokers than in nonsmokers. Reversible complications occurred in 17.5% of the smokers and 15.5% of the nonsmokers. Severe irreversible changes occurred in 28% of the smokers versus 15.2% of the comparative group of nonsmokers (P less than 0.01). The injuries caused by smoking not only reduce the biologic effectiveness of ionizing radiation but also increase the rate of side effects due to the deficient capacity for regeneration of the tissue surrounding the tumor. With diabetes as a complication, however, no significant changes in frequency of side effects were noted. Five-year survival in diabetic patients was affected in Stage I and II, but not in the advanced stages.