Imprint preparations were performed on bone marrow biopsy specimens obtained from the posterior superior iliac spine of 310 consecutive patients. Bone marrow aspiration was attempted prior to biopsy. When aspiration was impossible or inadequate, imprint preparations were used in order to study cytologic detail and enhance interpretation of the biopsy specimen. Malignant infiltrates were present in 22 (7.1%) of the 310 biopsy specimens including: non-Hodgkin's lymphoma, 12 patients, metastatic carcinoma, 6; Hodgkin's disease, 1; multiple myeloma, 1; Waldenstrom's macroglobulinemia, 1; and Sezary's syndrome, 1. An aspirate could not be obtained in 8 (36%) of 22 cases, but malignant cells were found in imprint preparations of the biopsy specimens. This study demonstrates that imprint preparations of bone marrow biopsies are useful in evaluating patients with malignancy when bone marrow aspiration is inadequate.