Details of positive blood cultures obtained from 357 inpatients attending the Toyama University Hospital were collected over a 10-year period in order to document changes in microbiological and clinical features of bacteraemia. Fifty-one per cent of patients were over 60 years old, 48% had intravascular catheters in-situ, and 17% had had surgical procedures within 30 days prior to the isolation of organisms from the blood. The proportion of underlying diseases other than malignancies increased over the 10-year period (42-60%, P < 0.05). Patients from surgical departments other than the Academic Department of Surgery increased over the study period (16-55%, P < 0.05). Staphylococcus aureus bacteraemia increased significantly (29 to 49%, P < 0.05) as did pseudomonas and anaerobic bacteraemia. Most bacteria showed no significant changes in their antibiotic sensitivity pattern over the 10 years. Clinical features in patients with bacteraemia varied with the infective organisms and the underlying disease. Mortality was high in patients with haematological malignancy, usually in association with Pseudomonas aeruginosa.