Background: Clinic care for morbid obesity is not very effective. Bariatric surgery is being considered the best way of intervention for this kind of obesity. Aim : Evaluate the clinical and nutritional evolution during the first year of obese women submitted to Roux-en-Y gastric bypass. Method : Retrospective series non-concurrent with 61 women. The variables were weight, BMI, weight loss percentage, loss of excessive weight percentage, waist circumference, hip circumference, lipid profile, daily use of supplements, practice of physical exercise, occurrence of sickness, nausea, constipation, diarrhea, asthenia, alopecia, dry skin, cramps and brittle nails. Results : They presented significant weight and IMC reduction as well as improvement in their lipid profile, in all consultations. After one year they presented 36,6% loss of the initial weight and 75% loss of excessive weight. The waist circumference also presented a considerable reduction on all the moments, decreasing from 122,1±13,4 cm to 94,1±10,6 cm. Regarding the intercurrences, the most frequent were alopecia, asthenia, dry skin and cramps. Conclusion : The Roux-en-Y gastric bypass was effective in promoting and maintenance weight loss during the period of the first postoperative year.