Epidemiological studies indicating that exposure to organic solvents is a risk factor for haematological malignancies are reviewed. Exposure to benzene is a risk factor for ANLL. A preleukaemic phase with pancytopenia is common and may be associated with a normo- or hypercellular marrow with morphological characteristics suggesting MDS. There are indications that other organic solvents than benzene may be leukaemogenic. Certain chromosome aberrations are characteristic in leukaemic cells from solvent exposed ANLL patients. The average latency time from start of occupational exposure until diagnosis is about 10-11 years. There is epidemiological evidence that exposure to organic solvents may also increase the risk of lymphoproliferative malignancies, i.e. ALL, NHL, HD and myeloma.