Forty-eight cases of dogs with primary and metastatic hepatic neoplasia were reviewed to determine if a predictable relationship between sonographic appearance and neoplastic cell type could be found. A focal mass was almost always a hepatocellular carcinoma (14 of 15) and 71% of these were hyperechoic. Focal or multifocal hyperechoic masses were most likely to be carcinomas (14 of 15). Focal or multifocal mixed neoplasms were most likely to be carcinomas (6 of 7). Two distinct patterns of lymphosarcoma were found: diffuse, mildly hyperechoic (6/11) and multifocal, hypoechoic (5/11). No neoplastic cell-type predictions could be made for focal or multifocal hypoechoic lesions. Diffuse fine or coarse patterns with minimal architectural distortions could be mistaken for normal or degenerative processes. However, in the presence of increased serum liver enzyme values, these subtle sonographic changes would warrant a liver biopsy to differentiate neoplastic infiltrate from non-neoplastic infiltrative and degenerative processes.