Here we describe hemopoietic chimeras serving as a mouse model for NUP98–HOXA9‐induced leukemia, which reproduced several of the phenotypes observed in human disease. Mice transplanted with bone marrow cells expressing NUP98–HOXA9 through retroviral transduction acquire a myeloproliferative disease (MPD) and eventually succumb to acute myeloid leukemia (AML). The NUP98 portion of the fusion protein was shown to be responsible for transforming a clinically silent pre‐leukemic phase observed for Hoxa9 into a chronic, stem cell‐derived MPD. The co‐expression of NUP98–HOXA9 and Meis1 accelerated the transformation of MPD to AML, identifying a genetic interaction previously observed for Hoxa9 and Meis1. Our findings demonstrate the presence of overlapping yet distinct molecular mechanisms for MPD versus AML, illustrating the complexity of leukemic transformation.