In 107 patients with malignant Hodgkin and non-Hodgkin lymphoma, bone marrow was evaluated with scintigraphy, magnetic resonance (MR) imaging, and biopsy to detect bone marrow infiltration. Imaging and biopsy results were classified as normal (class 0), suggestive of reactive changes (class 1), or suspicious for infiltration (class 2). About one-half of biopsy and imaging results agreed completely. In patients with chronic lymphocytic leukemia, false-negative findings were frequent with both imaging techniques. Although a positive biopsy result is usually accepted as proof of bone marrow infiltration, results indicate that negative biopsy findings do not exclude tumor involvement. When suspected infiltration was found with MR imaging or scintigraphy but results were normal or suggestive of reactive changes in the first blind biopsy, repeat blind or guided biopsy helped confirm the imaging results. Autopsy findings in two patients completely confirmed previous results with MR imaging and scintigraphy, although findings at antemortem biopsy were different. Scintigraphy and MR imaging should be included routinely in the staging of malignant lymphoma as an adjunct to blind biopsy in the complete evaluation of bone marrow status.