Résumé : Out of 744 newly diagnosed ALL children under the age of 18 years treated according to the EORTC-CLCG protocols 58831 and 58832, 28 (4%) were infants less than 1 year of age. An elevated risk factor, which takes into account the sizes of the liver and spleen and the number of circulating blasts, was present in 25 cases. Most patients had non-common ALL. Among 15 patients studied by cytogenetics, nine present chromosomal abnormalities, six of them having a t(4;11) translocation. Complete remission was achieved in 86% of cases. One patient died in complete remission of therapy-related infection. The overall EFS is 43%. It is not statistically different in very young infants as compared to infants older than 6 months. Except for patients with AUL or with t(4;11) translocation, a continuous complete remission rate above 50% can be achieved with a median follow-up of 4 years. The results obtained in infant ALL with EORTC-CLCG protocols are currently better than those obtained with some other protocols, but remains inferior when compared to the ones obtained in older children. Thus, further improvements are needed and should be evaluated in large cooperative trials.