Chronic neutrophilic leukemia, which may be regarded a variant of myeloproliferative disease, is associated with mature peripheral neutrophilia, hepatosplenomegaly, tissue infiltration by mature and immature granulocytes, an elevated leucocyte alkaline phosphatase score, absence of the Ph1 chromosome and elevated vitamin B12. In the few cases described up to now thrombocytopenia and bleeding complications were frequently noticed. Here we describe two patients with chronic neutrophilic leukemia in whom thrombocytopenia and/or a profound defect of platelet function were the cause of death.