Bone marrow evaluation plays a critical role in staging and predicting prognosis in patients with Hodgkin lymphoma or non-Hodgkin lymphoma. Bone marrow can be the initial site of detection of lymphoma in patients with unexplained symptoms or cytopenias. A comprehensive evaluation of bone marrow includes complete blood counts, blood morphology, bone marrow aspirate, and generous core biopsy sections. Specialized testing should be used in a logical fashion on a case by case basis.