Fusariosis has been considered an emerging infection in patients with haematological malignancies. In a multicentre retrospective study on filamentous fungi infections in patients with haematological diseases over a period of 10 years in Italy, fusariosis was documented in six patients from two of the 14 centres with a 0.06% incidence in acute leukaemia. A literature search yielded 177 cases of Fusarium infections in haematological diseases and acute leukaemia accounted for 71% of the underlying conditions. An increase from 0.5 to 3.8 cases per year was observed at the M.D. Anderson Cancer Center of Houston in the periods 1975-85 and 1986-95 respectively. Conversely, only 5.1 and 6.3 cases per year have been reported in the periods 1981-90 and 1991-96, respectively, from the other centres in the world. Half of the cases have been observed in the USA. In Europe, most of the cases have been observed in France and Italy. Invasive fusariosis is a rare complication in haematological diseases, as its overall frequency does not seem to be significantly increased within the last 20 years. However, its epidemiological distribution is not homogeneous and the possibility of local clusters of infections by this deadly pathogen should be carefully considered.