organ failure, including,liver toxicity, renal failure, and neurotoxicity, are frequent complications following HSCT which can affect the transplant outcome, morbidity, and mortality of allo-HSCT recipients: A retrospective study of 206 allo-HSCT patients was conducted to determine the frequency of organ failure and overall survival in patients receiving allo-HSCT. Liver toxicity, renal failure, and neurotoxicity were diagnosed according to clinical and laboratory records pre and post-allo-HSCT. A total of 33 patients (16%) developed organ failure within 200 days after allo-HSCT. Liver toxicity was diagnosed in 12% of patients, and the median time of its occurrence was 22 days (range: 0-207 days) post-allo-HSCT. Two percent (6 of 206) of allo-HSCT recipients presented renal failure. Renal failure was developed within the median time of 33 days (range: 5-88 days). Neurological involvement occurred in 0. 9% of patients. Among 206 patients, the frequency of complications such as veno-occlusive disease (VOD) and graft-versus-host disease (GVHD) was 1. 4% and 16. 01%, respectively. One-year overall survival of patients who had organ failure was 24%, and the mean survival determined 329±, 99. 58 days. Three-month overall survival of patients who developed liver injury and renal failure were 78% and 33%, respectively. organ failure remains a common complication in patients who received allo-HSCT. Patients with GVHD and two or multi-organ involvement seem to have lower overall survival.