A comparative analysis of radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques in determining placental protein 14 (PP14) levels in gynecologic patients was performed. Serum PPM levels were assessed in the patients in the last period of gestation, during menopause and in healthy nonpregnant controls. The possible discrepancy in PP14 levels was also examined in gynecologic patients with benign and malignant tumors. Both RIA and ELISA techniques proved to be sufficiently sensitive to measure PP14 concentration.