BACKGROUND Effectiveness of subtotal splenectomy, a procedure recently advocated as an alternative treatment to total splenectomy for patients with hereditary spherocytosis (HS), has been evaluated. METHODS Eighty-eight patients (74 children) with HS were included in this series. Clinical presentations ranged from asymptomatic cases to severe transfusion-dependent forms. Stunting of growth occurred in four cases; chronic fatigue was observed in 30 cases and cholelithiasis in 21 cases. Among the red cell indices measured by laser light scattering on Technicon H2, the most reliable for diagnosis was the abnormal percentage of hyperdense red cells (98% of HS patients). Osmotic gradient ektacytometry, used to measure membrane deformability and impairment of maximal deformability due to a reduction of erythrocyte surface, always showed the characteristic curves of HS. RESULTS Subtotal splenectomy was performed in 24 patients leading to a remnant spleen of about 25% of normal for age volume. This decreased the hemolytic rate while adequately sustaining the phagocytic function of the spleen (assessed by percentage of "pitted erythrocytes" and technetium 99n scans of the remnant). However, the observed reduction in hemolytic rate was not as extensive as that observed after total splenectomy (six cases) and subtotal splenectomy did not entirely prevent risk of cholethiasis (three cases). CONCLUSIONS This subtotal splenectomy (+/-cholecystectomy) has to be particularly considered for children with transfusion-dependent forms of HS, in order to obtain the benefits of increased hemoglobin levels without the pending risk throughout life of overwhelming post-splenectomy infections.