OBJECTIVE Cohort study from February 2003 through May 2011 to determine weight restoration and refeeding complication outcomes for patients with anorexia nervosa (AN) treated in an integrated inpatient-partial hospital eating disorder program designed to produce rapid weight gain and weight restoration in the majority. METHODS Consecutive admissions (females and males, adolescents and adults; N = 361 patients, 461 admissions) at least 1.8 kg below target weight with AN or subthreshold variants were included. Main outcome measures were rates of hypophosphatemia, transfer to medicine, or death; rates of weight gain and percent achieving weight restoration. RESULTS Hypophosphatemia was present in 7.9% of cases at admission and in 18.5% at some point during treatment. Hypophosphatemia was mild to moderate. Lower admission body mass index (BMI), but not rate of weight gain, predicted hypophosphatemia [OR = 0.65; p < .00001 (95% CI 0.57-0.76)]. Five patients (1.1%) were transferred to medicine or surgery, none because of refeeding. There were no deaths. Mean inpatient weight gain was 1.98 kg/week; mean partial hospital weight gain was 1.36 kg/week. By program discharge, 71.8% of adults reached a BMI of 19, 58.5% a BMI of 20. For adolescents, 80.4% came within 2 kg of their target weight; 76.1% came within 1 kg. CONCLUSIONS Refeeding patients with AN using a hospital-based, behavioral protocol may be accomplished safely and more rapidly than generally recognized, weight restoring most patients by discharge. Helpful elements may include the program's integrated, step-down structure; multidisciplinary team approach emphasizing group therapy to effect behavior change; and close medical monitoring for those with BMI < 15.