BACKGROUND: The aim of this study was to evaluate the morbidity and mortality attributable to smoking. MATERIAL AND METHODS: A transversal study was performed in a reference population of residents of the province of Granada (Spain). The number of deaths in 1985, the number of patients admitted to public hospitals in 1987 and a sample of out patients in 1989 were gathered from the National Institute of Statistics and hospital registries, and a prospective collection from out patient clinics was also carried out. The diseases studied included: oropharyngeal, esophageal, pancreatic, laryngeal, lung, bladder and kidney carcinomas, ischemic cardiopathy, cerebrovascular stroke, peripheral arteriopathy and chronic obstructive lung disease (COPD). Statistical analysis was performed by populational etiologic fraction and the chi square test. RESULTS: Four point five percent of the total number of annual hospital admissions, 6.3% of the out patients, 15.9% of the mortality and 12.0% of the total number of potential years of life lost (TPYLL) were estimated to be attributable to smoking in individuals over the age of 15 years in the province of Granada. The most frequent causes of morbidity attributable to smoking were COPD and ischemic cardiopathy, and with regards to mortality, ischemic cardiopathy (28.5%), COPD (21.6%) and lung cancer (17.5%). Higher percentages were observed in males than in females and in the group from 46 to 65 years of age. CONCLUSIONS: Smoking is not only responsible for an important percentage of deaths, but also leads to premature death and a reduction in the quality of life which is translated into an excess of health care costs. Since the impact of smoking becomes particularly evident from 46 to 65 years of age, smoking prevention should be centered on the early years of life.