The spleen is a large lymphoid organ located in the abdomen that filters blood and regulates the immune system. The extent of mobilization of splenic immune cells to peripheral tissues in health and disease, however, remains poorly understood. This is due, in large part, to a lack of in vivo , spleen-specific lineage tagging strategies. Here, we describe a detailed practical protocol of spleen transplantation and its evaluation for long-term graft survival. Unlike implantation of splenic morsels in the great omentum, our approach uses arterial and venous anastomoses which rapidly restores blood flow and facilitates long-term survival of the graft. The use of congenic mouse strains permits the use of immunofluorescence and flow cytometry-based methodologies to unambiguously track the migration of spleen-derived cells to peripheral tissues.