We analyzed 30 peripheral blood stem cell transplantations (PBSCT) from 25 human leukocyte antigen (HLA) matched sibling donors (MSD) and 4 HLA-matched unrelated donors (MUD) in 29 patients, done between November 1996 and March 2003. Patients aged 3 to 17 years underwent allogeneic PBSCT for malignant (16 patients) and non-malignant (13 patients) diseases. Sibling donors aged 3 to 23 years were given granulocyte colony-stimulating factor (G-CSF) 5-10 microg/kg/day for 4 to 5 days. All but one of the 29 donors underwent one single leukapheresis for stem cell collection. The patients received a median of 4.2 x 10(6) CD34+ cells/kg of body weight, they all engrafted after a median of 13.5 days (range 10-25 days). Acute graft-versus-host disease (GVHD) grade II to IV developed in 11 of 26 MSD transplants and in all 4 patients after MUD PBSCT. Eleven of 27 evaluable patients experienced chronic GVHD. After a median follow-up of 662 days, 20 out of 29 patients (69%) are alive, three of them need systemic immunosuppression for chronic GVHD. Six patients experienced relapse of their underlying malignant disease, one of them still alive in complete remission. Two patients died of grade IV acute GVHD and two others due to an opportunistic infection. Based upon our experience, PBSCT is a feasible and safe method for both pediatric donors and patients. It is associated with rapid engraftment, no greater incidence of acute but a higher incidence of chronic GVHD as compared to bone marrow transplantation (BMT) and therefore suitable mainly for children suffering from malignant diseases.