Fourteen steroid cell tumors (SCTs) of the ovary were studied by immunohistochemistry including inhibin, calretinin, CD99, Melan A, androgen receptor, and AE1/3. Twelve tumors were primary and 2 were recurrent. The primary tumors included 5 stromal luteomas (SL), 5 SCTs, not otherwise specified, and 2 Leydig cell tumors, 1 of the hilar type and 1 of the nonhilar type. All tumors were classified according to the predominant cell type. Six tumors were eosinophilic cell type, 3 clear-cell type, and 5 were mixed eosinophilic-clear-cell type. Inhibin, calretinin, and CD99 were positive in all 14 tumors. Twelve of 14 tumors (86%) were positive for Melan A and 9 of 14 (64%) for androgen receptor. AE 1/3 immunopositivity was found in 5 of 14 tumors (36%). Immunohistochemistry helps in the distinction between SCTs of the ovary and other primary or metastatic ovarian neoplasms with eosinophilic and clear-cell histology. In addition, immunohistochemistry can confirm the presence of recurrent SCT, if no sufficient clinical history is provided. As some SCTs can be positive for epithelial markers and histologically similar epithelial tumors can be positive for sex cord stromal markers, the use of multiple immunohistochemical stains is recommended.