The clinico-pathologic features, incidence and pattern of presentation of patients with the rare hairy cell leukaemia in University of Benin City Teaching Hospital, a major tertiary health centre in Niger Delta region of Nigeria have not been previously documented. All cases that presented from 1993 to 2003 were reviewed and this rare leukaemia constituted 1.5% of all haematological malignancies. Median age at presentation was 40 years. Typical clinical signs of pancytopenia and massive splenomegaly were found. Lymphadenopathy was rare. Normalization of pancytopenia was achieved by splenectomy followed by cytostatic agents but increased susceptibility to infection was not reduced. Four patients received interferon-alpha two patients, cladribine with prednisolone following splenectomy.