Background: The survival of children with acute lymphoblastic leukemia (ALL) has greatly improved in recent decades. Aim: We aimed at evaluating the outcome of children with ALL and their prognostic factors. Materials & Methods: A prospective study included 200 newly diagnosed pediatric ALL patients from 2009 to 2017. All patients were treated according to the modified total therapy study XIIIB for higher risk ALL adopted from St. Jude Children's Research hospital (SJCRH), USA. Results: Favorable age (< 10 y) and total leucocytic count (TLC) (≥ 50x10⁹/L) occurred in 75% and 69%, respectively. B-precursor ALL represented 82.5%. Central nervous system (CNS) involvement occurred in 4.5%. High-risk patients represented 47%. Complete remission was achieved in 92.5% and was significantly affected by the early morphologic response of BM d15, while it wasn't related to the phenotype. Eight- year overall survival, disease-free survival, and event-free survival were 77 ± 3%, 70 ± 4%, and 66 ± 3%, respectively. Adverse events included induction deaths (4.5 %(, refractory leukemia (3%), relapse (23.2%), secondary AML (0.5%), and deaths in remission (3.5%). By multivariate analysis, unfavorable age group ≥ 10 years, hyperleukocytosis, and patients with slow early response were the only ones associated with unfavorable impact on the outcome. There was statistical significant difference between standard and high risk for B-precursor ALL but not for T- precursor ALL. Conclusion: We concluded that treating children with ALL through modified TXIIIB protocol improved the survival at our institute than previous and the early response to treatment has a strong implication on the outcome.