Between years 1993 and 1998, 113 children aged from 6 months to 18 years (41 girls and 72 boys) with first relapse of acute lymphoblastic leukaemia (ALL) were included in the study. All children were treated according to BFM-90 relapse protocol. Thirty-two cases were classified as very early relapses, 56 as early and 25 as late relapses. Sixty-one children had isolated bone marrow relapse, in 30 children extramedullary relapse occurred (in 21 children in central nervous system and in 16 children in testes). There were 23 combined relapses. Remission was achieved in 12 children with very early relapse (78.12%), 32 children with early relapse (85.71) and 19 children with late relapse (96%). Event-free survival in 30 months of follow-up was 29.2%, 59.0% and 73.2% for very early, early and late relapses, respectively. Sixteen children with relapsed ALL after chemotherapy according to BFM-90 relapse protocol underwent high-dose therapy with hematopoietic stem cell transplantation (in 3 cases autologous and in 13 cases allogeneic). In 6 children isolated bone marrow relapse occurred after transplantation, all of them died during subsequent chemotherapy. Ten children is alive and well from 2 to 43 months after transplantation. The results obtained with BFM-90 chemotherapy in children with first early relapses are not acceptable. Such patients require high-dose chemotherapy and transplantation of hematopoietic progenitor cells.