Yolk SAC tumors make up 14% to 20% of all malignant ovarian germ cell tumors. Serum alpha-fetoprotein (AFP) levels are elevated in a significant number of patients and are useful for monitoring the response to treatment and for post-treatment surveillance. Surgery is required for diagnosis, staging, and treatment. The first case is a 12-year-old girl presented with abdominal pain. The ultrasonography (US) showed a huge pelvic tumor. AFP level was high (1000 mg/ml). Right salpingo-oophorectomy and pelvic lymphadenectomy were done. Histopathology reported yolk SAC tumor of ovary. She received 3 courses of bleomycin, etoposide, cisplatin (BEP). The second case is a 25-year-old G1AB1 presented with pelvic pain and distension. The US showed a huge pelvic tumor in the right abdominopelvic region. AFP level was high (1000 mg/ml). Right salpingo-oophorectomy, omentectomy, and appendectomy were done. Histopathology reported yolk SAC tumor of ovary. The patient received four cycles of BEP protocol; AFP level decreased to 10 mg/ml after the four cycles of chemotherapy. The third case is a 21-year-old girl presented with abdominal pain. The US showed a huge pelvic tumor in the right adnexa. AFP level was high (8700 mg/ml). Right salpingo-oophorectomy and pelvic lymphadenectomy were done. Yolk SAC tumor is rare in children and it could be cured usually. In this study, we described three patients with ovarian yolk SAC tumors and their fertility preservation treatments.These cases has reminded that in young age with high AFP levels and rapidly growing ovarian mass, diagnosis of the yolk SAC tumor has to be kept in mind.