Thirty-five cases of carcinoid metastatic to the ovary were analyzed from a clinicopathologic viewpoint. In 25 patients the ovarian tumors were discovered at laparotomy; in t h e remaining cases, t h e ovarian involvement was detected only at autopsy as a manifestation of widespread metastasis. Although one ovary was almost always enlarged, the opposite ovary was frequently enlarged also. Both ovaries contained tumor with only t w o exceptions. Abnormal urinary levels of 5-hydroxyindole acetic acid were often detected within several months after the operation. In all but five cases evidence for a primary carcinoid in the intestine or elsewhere was found. The prognosis was poor, with one-third of the patients dying within 1 year, and two-thirds within 4 years after the diagnosis of ovarian involvement. Although a metastatic ovarian carcinoid is often misinterpreted as a Brenner tumor or granulosa cell tumor, the most difficult diagnosis t o exclude is primary carcinoid, which, in an unpublished series of 34 cases, was always unilateral and was usually associated with the presence of other teratomatous elements within the tumor. VARIAN CARCINOIDS ARE RARE, ESPECIALLY 0 the metastatic forrns,l4 which almost always originate in the intestine. In a recent review, Shuster et al.25 found only 8 cases of metastatic ovarian carcinoid reported since 1955; a more complete survey of the literature has revealed a total of 25 cases.