Lactic dehydrogenase (LDH) is a glycolytic enzyme that may be elevated in the serum of patients with gonadal and extragonadal germinomas. In this report, a case of unilateral ovarian pure dysgerminoma with remarkably elevated levels of serum LDH is presented. After complete excision of the tumor, serum LDH levels promptly returned to normal levels. Although an electrophoretic pattern of serum LDH isoenzymes was within normal limits pre-operatively, an increase in LDH-1 and 2 was found 1 week after operation. Seventeen additional examples of ovarian dysgerminomas with elevated serum LDH levels have been reported in the English literature including five cases who had high levels of two fast fractions of LDH. These data suggest that serum LDH levels and its isoenzymes pattern are useful tumor markers for diagnosis and post-therapy surveillance in patients with ovarian dysgerminomas.