BACKGROUND Juvenile granulosa cell tumors (JGCTs) are rare ovarian neoplasms that typically occur in children and young women. While most JGCTs are diagnosed in Stage IA and can be cured by unilateral oophorectomy alone, the remainders are diagnosed in more advanced stages and may exhibit aggressive behavior despite surgery and chemotherapy. Paraneoplastic hypercalcemia occurs in 5% of ovarian malignancies with small cell and clear cell carcinoma being the commonest ovarian tumors associated with hypercalcemia. Only one case of ovarian JGCT associated with hypercalcemia has previously been documented in the literature. METHODS A 25-year-old married childless woman presented with a unilateral ovarian mass associated with profound hypercalcemia and suppressed serum parathyroid hormone-intact (PTH-i) level. After rectifying the hypercalcemia with saline hydration, furosemide, and anti-hypercalcemic drugs, the patient underwent unilateral salpingo-oophorectomy that demonstrated Stage IC ovarian JGCT. The patient received adjuvant chemotherapy with three courses of BEP (bleomycin, etoposide and cisplatin) and to date, ten months after surgery, she is disease-free, eucalcemic, and menstruating normally. CONCLUSIONS This is the second case reported in the literature of ovarian JGCT associated with hypercalcemia. Since serum PTH-i level was suppressed and the hypercalcemia did not recur after resection of the tumor, it is concluded that the hypercalcemia was caused by parathyroid hormone-related protein (PTH-rP) produced by the tumor. It seems that unilateral salpingo-oophorectomy followed by BEP chemotherapy is an appropriate treatment for unilateral Stage IC ovarian JGCT in women desiring to preserve ovarian function and childbearing capacity.