Background/Aim: The risk factors, clinical features and non-hematological toxicity profiles during chemotherapy in acute lymphoblastic leukemia (ALL) patients treated in pediatric hematology centres were analysed. Materials and Methods: A total of 902/1872 children were reported as having grade 3 or 4 toxicity. Results: Among the analysed toxicities, infection and gastrointestinal and liver toxicities were the most common. The median follow-up was 6.8 years. Overall survival and event-free survival rates for the analysed group were lower than those reported for the group without grade ≥3 toxicity. In univariate analysis, we identified the number of toxic episodes, the risk group and remission status that had a significant impact on the outcome. Multivariate analysis demonstrated the risk group and the number of toxic episodes ≥3 to be statistically significant for the results. Conclusion: The toxic profiles investigated in our report should be used in future efforts to decrease the burden of side effects during chemotherapy. Over the last years, there has been an improvement in the overall survival of childhood acute lymphoblastic leukemia (ALL), which is now around 80-90%. This is due to contemporary multidrug therapy regimens but, on the other hand, patients are burdened with severe complications of treatment (1, 2). Chemotherapy has a range of side-effects, such as infection, organ damage, hematological and other (malnutrition, hair loss). Most agents causing immunosuppression and myelosuppression increase the risk of bacterial, viral and fungal infections. The infection is still a major cause of death in ALL children (3, 4). Every organ may be adversely affected by anti-leukemic treatment, the most 1333 This article is freely accessible online.