Fifteen patients with hematological malignancies [9 acute nonlymphoblastic leukemia (ANLL), four chronic myelogenous leukemia (CML), two acute lymphoblastic leukemia (ALL)] received allogeneic peripheral blood stem cell transplantation (alloPBSCT) from HLA-identical sibling donors. Donors received 2.5-15 micrograms/kg/day of recombinant human granulocyte colony stimulating factor (rhG-CSF) for 5-10 days. Administration of rhG-CSF was well tolerated except for mild to moderate bone pain occurring in all the donors which was relieved by oral paracetamol. A total of 40 leukaphereses were performed for the 15 donors using the bilateral antecubital veins. None of the donors needed central venous line insertion. The median number of apheresis procedures for each patient was 3 (2-3). A median of 7.7 (4-38.2) x 10(8)/kg mononuclear cells, 35 (2.4-90.0) x 10(6)/kg CD34+ cells, 1.85 (0.45-4.8) x 10(8)/kg CD3 and 0.3 (0.16-1.01) x 10(8)/kg natural killer cells were given without any manipulation. Cyclosporin A (CsA) plus short-course methotrexate (MTX) (12 patients) and CsA alone (3 patients) were used for graft versus host disease (GVHD) prophylaxis. Median granulocyte and platelet engraftments were done on days 11 (10-31) and 16 (11-54) respectively. Grades II-IV GVHD occurred in 62% of the patients and grades III-IV in 15%. Twelve patients are still alive with full engraftment and disease-free. In conclusion, alloPBSCT is an alternative to allogeneic bone marrow transplantation, because of the ease of collection and rapid hematological recovery. However, there is a trend for increased acute GVHD in our leukemia patients compared to allogeneic bone marrow.