Metastatic tumors account for a significant proportion of the ovarian tumors that cause major problems in diagnosis for the surgical pathologist. This subject is reviewed with a consideration of the various patterns and cell types encountered in these tumors. The first two categories considered, tumors with endometrioid-like and mucinous appearances, include a variety of neoplasms originating in the gastrointestinal tract and its appendages that simulate closely primary ovarian endometrioid and mucinous tumors. Other important categories reviewed include several varieties of metastatic tumors with follicle-like spaces, small cell malignant tumors, and tumors characterized by cells with abundant eosinophilic cytoplasm. The review also includes a discussion of the general considerations that are helpful in the distinction of primary and metastatic ovarian tumors. Important recent reports in the literature concerning metastatic tumors are additionally summarized.