Background: Although the prevalence of smoking among medical students declined steadily between the 1960s and 1980s, it seems to have stabilized in recent years. Objectives: To evaluate temporal trends, over the last 17 years, in the smoking habits of medical students at the Universidade Federal de Pelotas, in the state of Rio Grande do Sul, Brazil, and to identify some possible risk factors for smoking. Method: Cross-sectional surveys with comparable methodologies were conducted in 1986, 1991, 1996 and 2002. Self-administered questionnaires were used. Smokers were defined as those who were smoking at least one cigarette per day for at least one month. Descriptive analyses were carried out, as well as crude evaluations using chi-square tests for heterogeneity and linear trend. In addition, Poisson regression, adjusted for age, was used in order to evaluate the effect of medical school class year on the incidence of smoking. Results: The prevalence of smoking among UFPel medical students was 10.1%, statistically similar to values found in 1991 and 1996. No differences in smoking frequency were found relating to sex, age, or parental smoking. The prevalence of smoking was found to increase progressively over the course of medical school. Conclusions: The downward trend in smoking prevalence among UFPel medical students is being replaced by a stable rate of approximately 10-15%. Anti-smoking campaigns are still necessary in university environments, especially in medical schools.

Keywords: Smoking/trends. Smoking/epidemiology. Medical students/tobacco use cessation. Cross-sectional studies. Questionnaires.