Sixty consecutive percutaneous fine-needle aspiration biopsies guided by ultrasound were performed without complications in patients with ultrasonically suspected focal or diffuse neoplastic liver disease. Evaluations of aspirated samples were based on cytologic examination of smear preparations (100%) combined with histologic examination of serial sectioned tissue fragments (81.7%). The overall accuracy rate of cytohistologic evaluations was 91.6% with a sensitivity of 92.2%, a specificity of 88.9%, and a high predictive value of positive results (cytology; 97.8%; histology, 100%). Percutaneous fine-needle aspiration biopsy guided by sonography proved to be a safe, useful, and highly accurate technique for making cytohistologic diagnoses of hepatic masses suspected of being malignant. No relationship was found between the various echo patterns of intrahepatic neoplastic lesions and cell type or primary site of tumor origin.