OBJECTIVE The purpose of this study was to investigate the relationship between premorbid weight and weight upon referral for inpatient treatment in patients with anorexia nervosa (AN). METHODS Forty-nine consecutively ascertained female inpatients with AN were asked to recall their premorbid body weights as well as their ages at onset of the illness. Premorbid body mass indexes (BMIs) and BMI percentiles were calculated for 42 of the patients and related to the BMIs upon initial referral for inpatient treatment. RESULTS Low premorbid BMI centiles were associated with a low BMI at referral. Vice versa, patients with an above average premorbid body weight had a higher BMI at referral. The largest absolute weight losses also occurred in those patients who had an above average premorbid body weight. CONCLUSIONS In conclusion, premorbid body weight explains a proportion of the variance of body weight at referral.