Association between anorexia nerviosa (AN) and low bone mass has been demonstrated. Bone loss associated with AN involve hormonal and nutritional impairments, though their exact contribution is not clearly established. We compare bone mass in AN patients with women of similar weight with no criteria for anorexia nervosa, and a third group of healthy, normal-weight, age-matched women. The study included 48 patients with AN (DSM-IV criteria), 22 healthy eumenorrheic women with low weight (LW Group; BMI <18.5 kg/m2) and 20 healthy women with BMI >18.5 kg/m2 (Control Group), all of similar age. We measured by DEXA lean body mass, percentage of fat mass, total bone mineral content (t BMC) and bone mineral density in lumbar spine (BMD LS) and total (BMD T). We measured anthropometric parameters, leptin and GH. The control group had greater BMD T and BMD LS than the other groups, with no differences between the AN and LW groups. No differences were found in BMD T, BMD LS and t BMC between the restrictive (n=25) and binge-purge type (n=23) in AN patients. In AN, minimum weight (P=0.002) and percent of fat mass (P=0.02) explained BMD LS variation (r2: 0.48) and minimum weight (r2: 0.42; P=0.002) for BMD T in stepwise regression analyses. In LW group, BMI explained BMD LS (r2: 0.72; P=0.01) and BMD T (r2: 0.57; P=0.04). We concluded that patients with AN had similar BMD as healthy thin women. Anthropometric parameters could contribute more significantly than estrogen deficiency in achievement of peak bone mass in AN patients.