Background. Primary insular carcinoid tumor of the ovary is a rare tumor and accounts for fewer than 1% of all cases of carcinoid in the body. With the exception of a single reported case, all previously described functioning ovarian carcinoid tumors have measured at least 10 cm in diameter. Thus, there appears to be a good correlation between the size of the tumor and the presence of the carcinoid syndrome. Case report. We describe a case of a functioning primary insular carcinoid tumor of the ovary measuring just 6 cm in maximal diameter. Conclusion. Although primary ovarian carcinoid tumor is very rare, a high clinical index of suspicion must be maintained, especially in a patient presenting with carcinoid syndrome and a small adnexal mass.