the aim of this study was to verify smoking cessation rates and associated factors. the study was performed in greater metropolitan belo horizonte and the town of bambuí, both in the state of minas gerais, brazil. study participants included 13,261 and 1,018 adults (> 20 years), respectively, randomly selected among residents of each area. the smoking cessation rate was 40.6% (95%ci: 39.1-42.3) in greater metropolitan belo horizonte and 38.8% (95%ci: 34.4-43.1) in bambuí. in greater metropolitan belo horizonte, smoking cessation showed an independent and positive association with age (> 40 years), schooling (4-7 and > 8 years), number of chronic conditions (> 2), and number of medical visits in the previous year (1-3 and > 4), and a negative association with marital status (unmarried). bambuí showed an independent and positive association with age (> 40 years) and a negative association with number of hospitalizations in the previous year (> 2). the heterogeneity of factors associated with smoking cessation made it difficult to identify vulnerable groups in order to target prevention strategies. further research is important to elucidate this heterogeneity.