The aim of this study is to study the two cases of acute lymphoblastic leukemia (ALL) who relapsed as acute myeloid leukemia (AML). Presented here are reports of two cases of pediatric ALL who developed change of lineage to AML at relapse. This change in phenotype, which involves the conversion of one phenotype to other phenotype during the course of disease or at relapse is a rare phenomenon rarely described in literature. The immunophenotypic and molecular findings are described. The present study emphasizes the need of immunophenotyping and molecular workup at relapse. Also adds to the repertoire of the published literature on this rare entity.