We report a case of hypercalcemia in a 20-year-old woman with an ovarian seminoma. She had neither evidence of bone metastasis nor hyperparathyroidism. Hypercalcemia was well controlled by corticotherapy and chemotherapy, and remained normal after remission was obtained. Different patterns in paraneoplastic hypercalcemia are detailed, with emphasis on PTH-related proteins and vitamin-D metabolites. Eleven cases of neoplasm with hypercalcemia and elevated calcitriol level are reported in the literature. One of them is a seminoma. These elevated levels could be related either to a PTH-like protein, either to 1 alpha-hydroxylase activity in some tumoral cells. Three other cases of seminoma associated with hypercalcemia without dosage of vitamin-D metabolites are reported. Dosage of calcitriol might be performed in paraneoplastic hypercalcemia of seminoma.