Improvement in cognitive functions with weight gain in patients with anorexia nervosa leads to the assumption of cognitive functions decrease during long-lasting self-starvation. In the present study the effects of chronic undernutrition on learning abilities, in rodents were investigated in an open-field test and a passive avoidance paradigm. The findings suggest that cognitive deficits after a weight loss of 32% of normal weight may be caused by undernutrition. Further research is necessary to clarify other influencing conditions and identify the underlying biochemical mechanisms.