A patient is presented who had acute basophilic leukaemia with intense erythroblastic reaction. The patient, a 66 year-old man, complained of general malaise, increased abdominal perimeter and melena. Leucocytosis, as well as severe anaemia and thrombocytopenia, were found in his peripheral blood. Basophils were present in all maturation stages, along with 7% blast-cells showing basophilic stippling, and there were 210 erythroblasts per 100 white cells. Erythropoietic hyperplasia (75%) was found in the bone-marrow aspirate, without dyserythropoietic signs; the PAS-stain reaction was negative. Of the non-erythroid cells, 63% were basophils and 34% blast-cells, some of them showing basophilic stippling plus metachromasia for tholuidin-blue, positivity for omegaexonuclease and negativity for peroxidase stains. The diagnosis of acute basophilic leukaemia was confirmed upon demonstration of basophilic stippling in the ultrastructural study of the blast-cells. The patient developed acute liver failure and renal insufficiency which led him to death. The basis of the diagnosis of acute basophilic leukaemia is discussed, as well as the differential diagnosis with other conditions presenting with basophilia and the probably reactive erythroblastic increase appearing in this case.