Dietary factors have a significant impact on overall health and western diet (WD) disrupts arterial homeostasis, thereby promoting atherosclerosis. In our study, we investigated the effects of short-term WD on bone marrow vasculature and hematopoiesis in hypercholesterolemic mice. We found that WD rapidly remodels bone marrow arterioles, and these alterations persist even after WD cessation. The proximity between hematopoietic stem cells (HSCs) and arterioles increased with short-term WD, which was associated with a reduced HSC counts as well as an increased number of progenitor cells and a higher production of myeloid cells. Additionally, the remaining HSCs showed increased proliferation, potentially raising susceptibility to clonal hematopoiesis. Collectively, our findings show that short-term WD dramatically alters the bone marrow physiology with lasting consequences.