Marrow specimens from six patients with anorexia nervosa and three with involuntary starvation were examined for the presence of gelatinous transformation and marrow cell necrosis. Five of the patients had pancytopenia. Acanthocytes were present in the circulation of all nine. In only two patients was marrow cellularity adequate. Gelatinous transformation was present in every marrow specimen and was of a marked degree in eight. Marrow cell necrosis was identified in all nine marrow specimens. The necrosis was extensive in one specimen, focal in the others and limited to the areas of gelatinous transformation. Severe malnutrition was the single element common to all the patients.