Amongst 1,200 leukemie children treated between 1958 and 1971, 60 are in complete remission for more than 10 years and 100 for more than 7 years. There were 96 acute lymphoid and 4 acute myeloid leukemias. Ten patients who have relapsed in the past have not done so lately. The F/M sex ratio is 1.5. Poor prognostic features were initially absent in 2/3 of cases. In 1/3 there was associated hyperleucocytosis and/or tumours. 93 children are in remission, their treatment having been stopped for 1 to 12 years. Five children relapsed and 4 are in a second remission for more than 2 years. Two children died in remission: one from a hepatocarcinoma and one from cardiac failure. These patients have been shown to have the following: 1) normal growth; 2) normal puberty: 8 patients have been able to reproduce, giving 10 children, one with multiple malformations; 3) school achievement and later socioprofessional behaviour has been normal. The patients have often sought a medical or paramedical career. Sequelae are minimal, psychological problems being minimal in the child. With the protocols used, mean remission curve shows a plateau after 9 years and complete definitive care is achieved in 92 per cent of patients surviving at 7 years. The very distant future outlook is not known. No other malignant haematological disease has occurred but one child died from a carcinoma.