The use of animal models has revealed important mechanisms relevant to the development and treatment of human cancer. In recent years the zebrafish has emerged as an exciting new organism in which to model leukaemogenesis. The zebrafish model has distinct advantages over other animal models, most notably a capacity for forward genetic studies and rapid small molecule screens which can be used to dissect novel genetic pathways contributing to the development of leukaemia. Additionally, the high fecundity and optical clarity of the zebrafish make it an attractive organism in which to directly visualize the localization and development of normal and abnormal haematopoiesis in vivo. Until recently, targeting mutations to specific genes was technically difficult in the zebrafish, but new technology using chimeric zinc fingers to create targeted gene knockouts has made reverse genetic modelling possible and promises to deliver many new and exciting models. This review summarizes the benefits of using the zebrafish to study leukaemogenesis, reviews current zebrafish models of specific leukaemias, and gives an overview of future direction for the zebrafish in the study of cancer.