Abstract Aim: The aim of the study was to evaluate the usefulness of CA125 measurements in ovarian cancer diagnostics in pre- versus postmenopausal women. Material and methods: The study group consisted of 99 serum specimens of women diagnosed with ovarian cancer (28 pre- and 71 postmenopausal). The control group consisted of 86 specimens collected from women without any ovarian pathology (34 pre – and 52 postmenopausal). CA 125 measurements were performed with Zymed Laboratories CA 125 ELISA Kit. Descriptive statistics, including mean values, standard deviation (SD) and 95CI of CA 125 among pre- and postmenopausal women, were calculated. The usefulness of CA 125 measurements in ovarian cancer diagnostics was assessed by calculating specificity, sensitivity, positive and negative predictive rates among pre- versus postmenopausal women. Statistical calculation was preformed with the use of STATISTICA 6.0 StatSoft Inc. (2001)software (www.statsoft. com). Results: Higher CA 125 concentrations were observed in controls among pre- versus postmenopausal women (10,01±15,41; 95%CI: 4,63-15,39IU/ml vs. 8,88±13,74; 95%CI: 5,06-12,71IU/ml, respectively, NS). In contrary, among women with ovarian cancer, CA 125 levels were higher in postmenopausal women when compared to premenopausal (352,11±432,07; 95%CI: 184,57-519,65 vs. 541,59±547,98 95%CI: 411,89-671,29, respectively, p<0,05). In premenopausal group the CA 125 sensitivity was calculated at 64% whereas specificity 94,12% (FPR 5,9%; OR: 10.9), positive predictive value 90% and negative predictive value 94,12%. Among postmenopausal women results were as follows: sensitivity 88,73%, specificity 98,07% (FPR 1,9%, OR: 46,7), positive predictive value 98,44% and negative predictive value 86,44%. Conclusions: CA 125 measurements were more useful in the postmenopausal group. Higher CA 125 levels were observed in women with ovarian cancer diagnosis when compared to controls, in which lower CA 125 were observed. Higher sensitivity, specificity and positive predictive values were observed in the postmenopausal group.