8270 Background: Bone marrow aspiration remains the easiest and cheapest method to document bone marrow metastases (BMM) of solid tumors. Methods: The results of bone marrow aspirates carried out in Hacettepe Institute of Oncology between 1993–2004 were reviewed. Hospital charts of solid tumor patients with an aspirate suggestive of a BMM were evaluated for associated clinical features. Results: Sixty-four patients (33 M, 31 F) were found to have BMM. Mean age ± SD was 50±13 years (range: 17–77). The most common diagnoses were breast (28%) and lung cancers (23%), followed by gastric (9%), prostate cancers (8%), and Ewing sarcomas (6%). Six patients (9%) had unknown primaries. Soft tissue sarcomas (3%), melanoma (1.6%), cancers of the nasopharynx (3%), larynx (1.6%), bladder (1.6%), rectum (1.6%), endometrium (1.6%), and testis (1.6%) were the other underlying tumors. Fifty-one percent of patients had BMM at diagnosis. Anemia and thrombocytopenia were present in 70% and 63% of patients, respectively, while neutropenia was less common (22%). Eight percent of patients had normal blood counts and 17% were pancytopenic. Mean hemoglobin was 10.5±2.4 g/dl (range: 5.9–16.5), WBC 8,100±6,700/mm3 (range: 2,200–44,800), and platelet 176,000±166,000/mm3 (range: 9,000–837,000). Bone metastasis was the most frequently associated clinical feature (72%). Median survival after the detection of BMM was 2 months (95% confidence interval: 0.7–3.3). One-year survival was only 14%. Conclusions: Breast and lung carcinomas are the most common causes BMM. Prostate cancer is also commonly associated with BMM, however, few patients with prostate cancer are followed in our clinic, and this may have altered our results. Blood counts may be variable, but commonly show moderately depressed counts in one or two of the lineages. Occasional patients may have totally normal counts. This condition carries an extremely poor prognosis. No significant financial relationships to disclose.