[en] An unclassified case of haemolytic anaemia with voluminous splenomegaly is reported. This anaemia was normocytic without any specific morphologic aspect of red blood cells (RBC); Coombs test was negative; the osmotic fragility was normal; the increased autohaemolysis was not affected by the presence of glucose; Hb studies were normal; no RBC enzyme deficiency was found; RBC lipids and membrane proteins were normal; there was a marked reduction in RBC survival with exclusive splenic uptake of erythrocytes. Before splenectomy, RBC cations and water content were abnormal: 1) the RBC water was decreased moderately; 2) the RBC sodium was about twice the normal mean with an increased ²²Na turn-over; 3) the RBC potassium was markedly reduced and ⁴²K influx was twice the normal mean; 4) the RBC calcium content was increased. Splenectomy was followed by rapid disappearance of haemolysis and RBC water and cation disturbances. Because of this extremely rapid disappearance after splenectomy the authors suggest this case of haemolytic anaemia could be a primary disease of the spleen. (author)