Brenner tumor of Ovary is a rare neoplasm of ovary affecting mostly post-menopausal women and constitute 2% of all ovarian tumors. It is mostly a benign tumor and malignant counterparts are a very rare occurrence. Brenner tumors are usually small and unilateral solid tumors. It is a type of surface epithelial tumor and the histogenesis is not clear. But the most accepted theory is it's origin from urothelial metaplasia of ovarian surface epithelium. Association of Brenner tumor with other neoplasms is a rare occurrence. We report here a case of unusually big benign Brenner tumor in association with a large mucinous cystadenoma with emphasis on it's clinical presentations, morphological spectrum and diagnostic morphologic features. A brief review of histogenesis of Brenner tumors has been submitted.