Levels of tissue carcinoembryonic antigen (CEA) in 54 abdominal fine-needle biopsy specimens from 50 patients were measured to ascertain the use of tissue CEA levels in diagnosis of malignancy. Biopsy was performed in the following sites: liver (n = 34), retroperitoneum (n = 8), adrenal gland (n = 3), pancreas (n = 2), omentum (n = 2), pelvis (n = 2), spleen (n = 2), and stomach (n = 1). Histologic findings proved malignancy in 39 patients and benign disease in 11 patients. In these 11 patients, the mean levels of tissue CEA were lower than the normal level of serum CEA (3 ng/mL). Tissue CEA levels were higher than serum CEA levels in nine patients with colonic carcinoma and in 12 of 16 patients with noncolonic CEA-secreting malignancies. Four patients with noncolonic CEA-secreting malignancies had tissue CEA levels within the normal range (less than 3 ng/mL). Tissue CEA levels were also normal in 13 patients with various non-CEA-secreting tumors. Tissue CEA levels may prove useful in biopsy of necrotic or cystic lesions and assessment of response to ablative therapy for colon metastases.