Comparative investigation of prostaglandin E (PGE) levels in primary malignant and benign epithelial tumors, metastases, and normal tissue of the ovaries has revealed more significant variations in PGE levels in malignant tumors than in benign ones. PGE content was reliably higher in adenocarcinomas as against benign tumors and normal ovarian tissue. No noticeable differences in PGE levels of benign tumors and normal tissue were revealed. The possibility of using arachidonic acid cyclooxygenase metabolism blockers in therapy of ovarian carcinoma, besides the common methods of treatment, is discussed.