context: the surgical treatment for morbid obesity is becoming common in this country. only a few papers reported the long-term results of the surgical approach for morbid obesity, mainly in terms of quality of life. objective: to compare mortality rate, weight loss, improvement of both diabetes and hypertension, and quality of life of patients from the public healthcare in cuiabá, mt, brazil, who underwent either medical or surgical interventions after a minimum of 2 years. methods: the population of this study was constituted by morbidly obese patients who initiated treatment between june 2002 and december 2006. the casuistic consisted of 89 patients submitted to medical therapy and 76 patients who underwent surgical procedures. the main variables were weight loss, improvement of hypertension and diabetes, quality of life, and mortality. results: the overall results showed that weight loss was significant in the two groups (p<0.001); however surgical patients showed a greater loss than the medical group (p = 0.05). the improvement of diabetes and hypertension was significantly greater in the surgical group (p<0.001), in which no cases of diabetes persisted. there was an increase in cases of hypertension among patients receiving medical attention. mortality occurred in six cases (6.7%) of the medical group and in five cases (6.6%) of the surgical group (p = 0.97). the median grade of the quality of life score obtained by surgical patients (2.37 [range: -2.50 to 3.00]) was significantly greater (p<0.001) when compared to the medical group (1.25 [range: -1.50 to 3.00]). conclusion: the surgical group presented better results regarding the weight loss, quality of life and improvement of hypertension and diabetes. there was no significant difference in mortality rate between the two groups after a minimum of 2 years.