Liver disease is a frequent complication in bone marrow transplant recipients and may occur early or late in the post-transplant period. Using ultrasound-guided fine needle (1.2 mm, 18 G) cutting biopsy, we studied six patients with undefined late post-BMT liver disease. No procedure-related complications occurred and all liver biopsies were informative, leading to changes in therapeutic approach. In our small series, the most frequent cause of hepatic damage was drug toxicity. US-guided fine needle cutting biopsy is a useful and easy tool for the work-up of unexplained post-BMT liver disease.