This study presents a comparative risk pattern for cancer of the oral cavity, pharynx and larynx, in relation to cigarette smoking and alcohol consumption based on data from case-control studies conducted in Korea Cancer Center Hospital, Seoul, Korea. The risk of cancer of the oral cavity, pharynx and larynx rose for current smokers and declined for ex-smokers. In males the odds ratios (ORs) for these sites rose with duration of smoking and number of cigarettes smoked per day. The relationship is strongest for laryngeal cancer. The risk for all sites was elevated linearly as amount and frequency of alcohol intake increased. Heavy drinkers, i.e. males who drank 90 g ethanol daily had an approximately 15-fold risk of cancer of the oral cavity, an 11-fold risk of pharyngeal cancer and an 11-fold risk of laryngeal cancer compared with non-drinkers. Alcohol drinking was a much stronger risk factor for cancer of the oral cavity than cancer of the pharynx and larynx. Alcohol was a much weaker risk factor for laryngeal cancer than cigarette smoking. Cancer of the oral cavity, pharynx and larynx also showed an interaction between smoking and alcohol, suggesting a synergistic effect.