We present a mortality case showcasing t(9;11)-positive acute myeloid leukemia/juvenile myelomonocytic leukemia (AML/JMML) overlap to shed light on this lethal molecular subtype of AML. In this case, the flawed assumption that JMML was to blame impeded the prompt undertaking of appropriate treatment for AML in our 14-month-old patient. This article aims to scrutinize the catastrophic sequel of such an overlap in leukemia and refutes the contemporary diagnostic methods.