The incidence of mixed-lineage leukemias in the pediatric age group was previously reported as 13.8% for myeloid antigen-positive ALL and 11.1% for lymphoid antigen-positive acute myeloid leukemia (AML). Recent studies showed that extensive chemotherapy protocols overcome the risk of myeloid lineage. Our study also supports most of the previous data and we postulate that myeloid antigen expression in pediatric ALL cases has insignificant effect on clinical presentation, relapse rates and survival. Importantly, 54% of myeloid antigen-expressing ALL patients received high-risk treatment protocols for some other reasons and this may also have contributed to similar outcome in these patients to that observed in myeloid antigen-negative ALL patients.