&NA;Hodgkin disease (HD) can involve the bone marrow (BM) with a reported incidence at time of initial staging that ranges from <5% to 20%. The presence of BM involvement by HD correlates with many factors including advanced nodal disease, systemic symptoms, age, peripheral blood cytopenias, tumor bulk, and histologic type of HD. The authors describe the case of a 43‐year‐old woman with a history of stage IB mixed cellularity HD who relapsed with HD in BM 9 months later. Bone marrow aspirate smears were negative for HD, but the biopsy specimen was extensively involved by HD, which was characterized by numerous mononuclear neoplastic cells and occasional Reed‐Sternberg cells in a mixed cellular background of eosinophils, plasma cells, and histiocytes with extensive fibrosis. Immunohistochemical studies of the neoplastic cells were positive for CD15, CD30, and Epstein‐Barr virus latent membrane protein type 1, supporting the diagnosis of HD. The role of BM biopsy in staging, the criteria for the diagnosis of HD in BM, and the role of immunohistochemical studies are reviewed. The differential diagnosis of HD involving the BM is also discussed.