Results of studies on predictives factors in eating disorders are not very clear up till now. Attention was focused primarily on the predictive value of eating behaviour, duration of illness, comorbidity and demographic variables in groups with mixed eating disorders, but lately more studies were published concerning the influence of psychological and personality features. In this four year follow-up study of 90 eating disordered adolescent patients predictive value of the behavioral and demographic variables is confirmed in the bulimic patients only. The prognostic value of psychological variables and personality characteristics analysed with the Eating Disorder Inventory and the Dutch Personality Questionnaire appear to be different for anorexic and bulimic patients. Unfavorable prognostic variables for anorexics are maturity fears and feelings of ineffectivity towards the demands of adulthood. For the bulimic patients low self esteem and strong feelings of inadequacy are related to a poor prognosis, together with a disturbed body image and poor interoceptive awareness.