Abdulkadir MohamadsaidAbdi Mulatu2026-06-172026-06-172025https://etd.aau.edu.et/handle/123456789/8165Background: Acute lymphoblastic leukemia accounts for approximately 75% of childhood leukemias worldwide. The overall survival exceeds 90% in high-income countries. The Outcome in low- and middle-income countries remains suboptimal, including Ethiopia (10–40%). Relapse is reported in 25–35% of LMIC cases and is a major contributor to mortality. Predictors of relapse in this setting remain insufficiently characterized. Methods: A retrospective cohort study included children younger than 18 years with newly diagnosed ALL treated at Tikur Anbessa Specialized Hospital between 2020 and 2025. Overall and relapse-free survival were demonstrated with Kaplan–Meier survival analysis, predictors for death and relapse were evaluated with R using bivariate and multivariate Cox proportional hazards models at p < 0.05. Results: A total of 251 children were included (male: female (1.5:1); median age 6.2 years; median follow-up 20.1 months). At diagnosis, 52.2% were standard-risk and 47.8% high-risk; nearly half were undernourished. Immunophenotyping and cytogenetic testing were infrequently performed. Infections accounted for 42 % of deaths, mainly during induction. Treatment abandonment occurred in 11.2%. OS was 74.9% at 1 year and 54.5% at 4 years. Relapse occurred in 14.4%, predominantly in the bone marrow (36.8%), with RFS of 70.5% at 1 year and 45.9% at 4 years. Relapse had a dismal outcome with an OS of 32.9 at 3 years. Infants had higher mortality (AHR 4.58 vs >10 years; AHR = 11.1 vs 1–10 years), and treatment abandonment increased mortality 2.41-fold. High WBC strongly predicted relapse: >100,000/μL (AHR = 7.47) and 50,000–100,000/μL (AHR = 3.52) compared with WBC <20,000/μL. Conclusion: Survival and relapse outcomes in pediatric ALL patients in Ethiopia remain suboptimal, with infant age, elevated WBC, infection, and treatment abandonment driving mortality and relapse. Strengthening supportive care, early diagnosis, and diagnostic capacity is crucial for improving outcomes.enPediatric Acute Lymphoblastic LeukemiaRelapseOutcomesTreatment AbandonmentPredictors for outcomesThesis