Cancer of the rectum is common in most industrialized countries. It is considered to be the result of a combination of environmental (diet, tobacco, alcohol, etc.) and genetic factors. We studied the evolution of morbidity and mortality due to cancer of the rectum and sigmoid in Spanish provinces and its relationship to different Spanish diet components. Our study covered the period 1977-1985. We used the indirect method to determine morbidity and mortality rates per 100,000 population, grouped according to age and sex. The consumption of different diet components was obtained from National Statistics Institute publications on the subject. These components were total lipids, animal fats, vegetable fats, butter and pork lard, margarine, fiber, and alcohol (all in g/person/day). For the study period, the mean national standardized mortality was 5.26 per 100,000 population and morbidity was 171.57 per 100,000. Provinces having rates above and below the national average were noted. The study revealed that, overall, alcohol consumption presents a 0.42 (p less than .001) positive correlation with standardized mortality, as does total lipid consumption.