Ten years of cumulative experience represented by 4,902 consecutive diagnostic bonemarrow examinations at a tertiary care and referral center were reviewed to assess the value of specific components. While it has been shown previously that the information obtained from each component is generally complementary, the inclusion of some or all components may vary between institutions. The components studied included aspirate smears, clot sections, biopsy cores, and touch imprints of biopsy and clot sections. Three clinical presentations accounted for the majority of cases: staging for carcinoma or lymphoma, cytopenias, and acute leukemia. We conclude that bilateral aspirates with biopsies are required for diagnosis in staging of neoplasms and that a unilateral aspirate with biopsy is sufficient to assess patients with cytopenia or leukemia. Only rarely were touch imprints of biopsy cores necessary to establish a diagnosis; however, their early availability prior to examining sections of the clot and core did provide immediate information, when positive, in the staging of patients with carcinoma. In a small percentage of staging and leukemia cases the diagnosis rested with the clot section alone. The findings in this study address common assumptions associated with routine diagnostic hematology and oncology procedures, and are important to both clinicians and pathologists concerned with accuracy, quality assurance, turnaround time, and cost containment. Am.