Changes in body weight, waist and hip circumferences, body composition, and skeletal status in women after bariatric surgery were evaluated. Thirty-six women [mean age 41.2 ± (SD) 9.5 years, weight 115.7±18.0 kg, and BMI 42.1±5.3 kg/m(2)] underwent laparoscopic sleeve gastrectomy. Bone mineral density (BMD) at lumbar spine, femoral neck, total hip, and total body, and body composition were evaluated at baseline and 3, 6, and 12 months after surgery.Weight, BMI, waist and hip circumferences decreased significantly. Total body bone mineral content (TBBMC) increased by 2.5±3.5%, and fat, lean body mass, total mass and fat-% decreased significantly by 38.9±12.0%, 15.4±5.9%, 26.5±8.1%, and 17.6±8.9%, respectively. Slight decreases in total body (0.6±2.2%) and spine (1.2±7.1%) BMD were not significant, whereas total hip and femoral neck BMD decreased significantly by 5.3±8.2%, and 6.2±7.0% (p<0.001). Change (Δ) in TBBMC correlated only with Δ in weight (r=0.38, p<0.05) whereas Δ in all other body composition parameters correlated significantly with Δ in body weight and circumferences (r=0.46-0.98). The Δ in BMD (except total body BMD) correlated significantly with Δ in body composition parameters (r=0.34-0.59). Baseline fat and lean content besides changes in body fat and lean mass accounted for bone changes. In conclusion, bone loss after bariatric surgery is related to post-operative changes in body composition, as well as to weight loss and decrease in waist and hip circumferences.