We investigated 90 autopsied cases with hematologic malignancy, including malignant lymphoma (ML), acute leukemia (AL), and adult T-cell leukemia (ATL) peculiar to our district, during the 10-year period 1982-1991 to determine the change in incidence of infection as a cause of death. We divided the cases into two groups representing the first half decade (1982-1986) and the second half decade (1987-1991) and compared the findings made in the two groups. Although infection was the major cause of death in those autopsied cases, the incidence of fatal infections decreased during the latter period. The incidence of fatal bacterial infections decreased, while fungal infections showed a relative increase. Pneumocystis carinii pneumonia and cytomegalovirus (CMV) infection occurred more frequently in patients with ATL than in those with ML or AL. Combined infection by more than three pathogens was observed in 2 cases of ATL. Our study revealed the characteristics of ATL specific to our district, and indicated the need to apply new strategies to prevent and treat fungal and viral infections in patients with hematologic malignancies.