A 71-year-old woman with Kaposi's sarcoma was admitted to the hospital because of severe pancytopenia with negative sternal aspirate. The bone marrow trephine biopsy demonstrated an extensive replacement of the hematopoietic tissue by Kaposi's sarcoma. Skin, soft palate mucosa, spleen, retroperitoneal and axillary lymph nodes were also found to be involved at the post-mortem examination. Therefore the bone marrow biopsy can be used in the staging of Kaposi's sarcoma in presence of pancytopenia and might be able to detect a primary visceral involvement in patients without cutaneous lesions.