The growth of 66 long-term survivors, transplanted in two centres (Genoa S. Martino and Monza) is reported. Patients were all under age 15 at the time of bone marrow transplantation (mean 9.8 +/- 3.4 years; range 1.07-15 years) with a minimum follow-up of at least 12 months. They were divided into four groups. Group 1: eight patients with severe aplastic anemia (SAA): conditioning included cyclophosphamide (CY) 200 mg/kg only. Group 2: 32 patients with acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML): conditioning included CY 120 mg/kg and 10-12 Gy fractionated total body irradiation (fTBI). Group 3: 20 patients with ALL, who had previously received cranial irradiation; conditioning included CY 120 mg/kg and fTBI with an additional testicular irradiation (4 Gy). Group 4: six patients with chronic myeloid leukemia (CML) and AML; conditioning included CY 200 mg/kg and busulfan (BU) 16 mg/kg. Group was impaired in all four groups, including the unirradiated groups (-0.2 +/- 0.7 and -0.5 +/- 0.6 delta-SDS in groups I and 4, respectively). Growth impairment-SDS was statistically significant in the two irradiated groups (-0.7 +/- 1.0 and -0.9 +/- 1.0 delta-SDS in groups 2 and 3, respectively), more marked in patients who had had previous cranial irradiation. Chronic graft-versus-host disease and its treatment were not found to have a major effect on growth.