MR imaging provides a highly sensitive and accurate means to depict tumor involving the peritoneum and bowel serosa. The ability of MR imaging to depict subtle peritoneal metastases plays a critical role in diagnosing and monitoring the oncologic patient with known or suspected peritoneal spread of malignancy. In this review I will describe the mechanisms of peritoneal tumor spread, and MR techniques and protocols for peritoneal imaging. A detailed description of the MR appearance of peritoneal tumor at different anatomic sites will be provided followed by a discussion of clinical applications for MR imaging of peritoneal malignancy.