In the present pilot study 52 inpatients with anorexia nervosa were examined with regard to cognitive impairments. A psychological assessment was made on admission (T1) and shortly before discharge (T2), the focus being on fluency aspects of cognitive functioning. The results showed high test scores at T1 on all cognitive measures and improvement in cognitive functioning in the course of inpatient treatment. However, the level of cognitive functioning was not correlated with weight loss or duration of illness. Patients who were discharged with a BMI below 17.5 kg/m2 scored even higher at T1 (reaction time, concentration task) than those with a BMI above 17.5 kg/m2, pointing to a negative association between cognitive performance and outcome (target weight). Psychopathological variables that may play a role and that should therefore be considered in future research are discussed.