This study investigated the clinical relevance of acute pancreatitis in allogeneic hemopoietic stem cell (bone marrow or peripheral blood) transplants (BMT). We studied 26 patients undergoing BMT. The preparative regimen was busulfan and cyclophosphamide in 17 patients and total body irradiation and cyclophosphamide in 9 patients. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin A and short-term methotrexate in all 26 patients. The pancreas was studied using amylase and lipase serum levels, abdominal contrast-enhanced tomography, and/or ultrasound. Clinical and laboratory signs of acute pancreatitis were found in two patients with acute hepatointestinal GVHD, and in one patient with acute hepatic GVHD and cytomegalovirus infection. This patient died of multiorgan failure, with interstitial acute pancreatitis at autopsy; the other two patients recovered with general supportive care and GVHD therapy. We suggest that in the patients with complications after BMT, particularly acute hepatic/hepatointestinal GVHD, and cytomegalovirus infection, the possibility of acute pancreatitis should be considered.