Surface epithelial-stromal tumors are the most common neoplasm of ovary in the reproductive age and beyond. Less than 1% of epithelial ovarian tumors occur before the age of 21 years while 75% of sexcord stromal tumors (Sertoli and Leydig Cell) occur in the third and fourth decades of life. Serous tumors rarely occur in combination with germ cell tumors, sex-cord stromal tumors or granulosa cell tumors. Thus it is extremely rare for a combination of the above two tumors to occur before 21 years although a case report for a tumor with epithelial, stromal and sex-cord stromal elements for a 58-year-old patient has been documented. We believe ours is the first case in literature of a massive Serous Cystadenoma with co-existing stromal tumor with minor sex-cord stromal (Sertoli-Leydig Cell) elements.