Central nervous system (CNS) relapse in childhood acute lymphoblastic leukemia (ALL) has been overcome by sensitive therapatic approachs. This study was planned to present the development of CNS relapse and survival in newly diagnosed 190 ALL patients whose cases were followed in the authors' unit between March 1991 and May 2002. St. Jude Study XI protocol was given to the patients who applied between March 1991 and March 1997 (group A) (n = 122), and St. Jude Study XIII protocol was given to the patients who applied between March 1997 and May 2002 (group B) (n = 68). The patients having isolated CNS relapse in group A received craniospinal irradiation (CSI) median 3.5 months after CNS relapse (range 2-6 months), a short time after reinduction, and 2 cures of consolidation. In group B, patients having isolated CNS relapse received IT once a month and a high-dose methotrexate treatment once every 8 weeks and 3 or 4, cures later therapy CSI median 7 months after CNS relapse (range 6-8 months) was given. When the overall survival rates of the 2 groups are compared, a statistically significant higher survival rate at 5 years was determined in group B than in group A (respectively, 82.3%, 58.4%) (p < .05). When subgroups of the patients (that is, those with no relapse, isolated CNS or BM relapse, or CNS + BM relapse) were compared in both groups, it was found that survival was much higher for the ones with no relapse and with isolated CNS relapse (respectively, 87.9%, 72.7%) compared to isolated BM or CNS + BM relapse groups (respectively, 10%, 13.3%) (p < .05). In a conclusion, for children with acute lymphoblastic leukemia and an isolated CNS relapse, with delayed definitive craniospinal irradiation allowing more intensive systemic and intrathecal chemotherapy results in better overall survival than has been previously reported.