Objective: To determine the prevalence of and factors associated with smoking among medical students, as well as to evaluate the profile of this group. Methods: A total of 316 medical students (98.7% of the total) at the University of Passo Fundo, in the city of Passo Fundo, Brazil, completed a self-report questionnaire with questions on tobacco intake and on attitudes related to smoking. In accordance with the World Health Organization guidelines, the students were classified as daily smokers, occasional smokers, former smokers or nonsmokers, those in the two first categories being considered active smokers. Results: We found that 16.5% of the students were active smokers (daily smokers, 5.4%; occasional smokers, 11.1%) and that 3.5% were former smokers. The mean age was 22.2 ± 2.4 years. Factors significantly associated with the smoking habit (p < 0.05) were male gender, paternal smoking, regular alcohol consumption and use of antidepressants or anxiolytics. For the majority (69.2%) of the smokers, the age at smoking onset was 15-19 years of age, and the main motivations to start smoking were selfinitiative and influence of friends. The conceptualization of smoking as an illness was significantly higher among the nonsmokers. In 70.6% of the smokers, tobacco intake was 1-10 cigarettes a day. Among the smokers, 92.3% agreed that smoking is harmful to health, 67.3% had tried to quit smoking, 96.0% believed themselves able to do so, and 87.2% intended to quit smoking. Conclusions: The prevalence of smoking remains significant among medical students. Therefore, it is fundamental that we develop more effective strategies for smoking prevention and cessation in order to reduce the number of smokers among future doctors. Keywords:Smoking; Prevalence; Students, medical; Behavior. ResumoObjetivo: Verificar a prevalência e fatores associados ao tabagismo entre os acadêmicos de medicina e avaliar o perfil desse grupo. Métodos: Responderam a um questionário autoaplicável, contendo perguntas sobre consumo e atitudes relacionadas ao tabagismo, 316 acadêmicos de medicina (98,7% do total) da Universidade de Passo Fundo. Segundo recomendações da Organização Mundial da Saúde, os estudantes foram classificados em fumantes diários, fumantes ocasionais, ex-fumantes ou não-fumantes, sendo considerados fumantes ativos os nas duas primeiras categorias. Resultados: Observou-se que 16,5% dos acadêmicos eram fumantes ativos (5,4% diários e 11,1% ocasionais) e 3,5% eram ex-fumantes. A média de idade foi 22,2 ± 2,4 anos. Os fatores significativamente associados ao tabagismo (p < 0,05) foram sexo masculino, pai fumante, uso regular de bebidas alcoólicas e uso de antidepressivos ou ansiolíticos. Verificou-se que 69,2% dos fumantes iniciaram o tabagismo entre 15 e 19 anos, tendo como principais motivações a vontade própria e/ou a influência de amigos. A conceituação do tabagismo como doença foi significativamente maior entre os não-fumantes. Quanto à carga tabágica, 70,6% dos fumantes consumiam 1-10 cigarros por dia. Entre os fumantes...