Since 1991, 2042 first hematopoietic stem cell transplants (HSCT) have been performed at the Hematology-Oncology and Stem Cell Transplantation Research Center at Tehran University of Medical Sciences. Acute myelogenous leukemia (548 patients), thalassemia major (335 patients) and acute lymphoblastic leukemia (275 patients) have been the most common transplanted disorders. There were 1418 cases that received allogeneic HSCT and 624 cases that have received autologous HSCT. The numbers of allogeneic and autologous HSCT have increased, but the allogeneic to autologous ratio has remained constant. The first peripheral blood hematopoietic stem cell transplantation was performed in 1996; since then, 1671 have been done. The donor types for 1418 allogeneic first HSCT were 1367 (96.4%) human leukocyte antigen (HLA) matched-identical siblings, 29 (2%) HLA-mismatched sibling/other relative, 13 (0.9%) syngeneic twins, 5 (0.4%) HLA-matched other relatives and 4 (0.3%) unrelated. The first cord blood hematopoietic stem cell transplantation was performed in 1998 and since then there have been 14 patients that have obtained cord blood transplantations. Recently, new methods have been used like donor lymphocyte infusion (DLI) and cellular therapy. There were 111 patients with cellular therapy for post-myocardial infarction, cirrhosis, thalassemia major, multiple sclerosis, head of femur necrosis and renal cell carcinoma.