Recent advances in cytogenetics and molecular biology have led to the realization that cancer is a genetic disorder. This finding is especially evident in acute leukemia where the identification of nonrandom cytogenetic abnormalities has paved the way for the discovery and characterization of associated oncogenes and novel mechanisms of leukemogenesis. New insights into the function of these genes and their products are beginning to provide information about their role in normal cell function and leukemogenesis. This article briefly reviews the most recent advances in this exciting field.