Sertoliform endometrioid carcinoma of the ovary (SEC) is an uncommon variant that bears histologic similarity to Sertoli and Sertoli-Leydig cell tumors (SLTs). Clinically, SEC affects an older population (60–70 years), while patients with SLT have an average age of 25 years and may exhibit endocrine manifestations. A number of histologic features can be used to distinguish the 2 entities, the most important ones being (1) the presence of areas with the usual pattern of endometrioid carcinoma, and (2) the presence of mucin at the apical borders of the tumor cells. Cytokeratin stains positively, while inhibin and calretinin stain negatively in SEC; the converse is true for SLTs. Based on the clinicopathologic behavior of this entity, SEC should be considered a well-differentiated carcinoma with relatively good prognosis if limited to the ovary.