In the present study, the course of inpatient weight gain was analysed in a sample of 40 female adolescent anorectic patients who had been readmitted for severe relapse. Longitudinal parameters were derived by statistical methods from the patients' weight curves during inpatient treatment. Results indicate a high risk of renewed weight loss throughout the first 9 months after discharge; 31 of the 40 patients had been readmitted within 12 months. Within the comprehensive set of clinical variables assessed, the weight curve parameters ‘negative variation of the weight curve’, ‘velocity of BMI increase’, and ‘mean BMI’ during inpatient treatment were significantly related to the tempo of weight decrease after discharge. The duration patients had maintained their target weight up to discharge appeared to predict time to re-admission. Thus, findings suggest that longitudinal weight patterns might be of prognostic significance with respect to post-discharge weight maintenance in anorexia nervosa, and hence are worthy of consideration in further treatment research. Copyright © 2002 John Wiley & Sons, Ltd and Eating Disorders Association.