The patients in the abovementiontal studies had known primary tumours and at present bone marrow aspiration /biopsy is routinely performed for staging of tumours ,but the high incidence of metastatic deposits found in these bone marrows emphasises the practicability of routine bone marrow aspiration in patient with suspected malignancy or severe alaemia It is difficult to determine from the literature the incidence of malignant cells in routine series of unselected bone marrow aspirates so we investigated the usefulness of routine bone marrow examination for the diagnosis of malignancies