The magnetic resonance (MR) features of primary and metastatic hepatic tumors were analyzed and compared with CT findings in 28 patients. MR images were obtained on a 0.35-Tesla superconducting magnet using a variety of spin echo and inversion recovery imaging techniques. The normal liver appeared homogeneous and of moderate intensity. Tumors typically appeared as masses of increased intensity on spin echo images and diminished intensity on inversion recovery images. Tumors had prolonged T1 and T2 times, which varied in different types of tumors and within regions of a single tumor. A specific T1 and/or T2 time could not be ascribed to any tumor. Tumor intensity varied greatly depending on the imaging techniques employed, becoming isointense with normal liver on some imaging sequences. MR and CT detected lesions equally well, but internal architecture and the relationship of tumors to hepatic vascular structures were better displayed on MR.