A case-control study compared the natural history of cigarette smoking in alcoholic and nonalcoholic populations to determine why alcoholism and smoking are closely associated. Eighty-three percent of alcoholics were smokers compared to 34% of the nonalcoholic subjects. Compared to other children, children who later became alcoholic were more likely to become regular users of tobacco once they had tried it. Only 7% of alcoholic smokers were successful in their attempts to quit smoking compared to 49% of the nonalcoholic smokers. More research comparing the smoking cessation efforts of alcoholics and nonalcoholics is needed to confirm these findings. Alcoholism is estimated to be 10 times more common among smokers than among nonsmokers. Possible explanations for this include a susceptibility on the part of some individuals to addictive drugs in general, and/or for some individuals tobacco smoking and alcoholism are both sequelae of a propensity to behave irresponsibly.