Objective:To identify the loss of heterozygosity (LOH) on chromosome 17p13.3 in ovarian cancer and cervical cancer. Methods: The frequency of LOH on chromosome 17p13.3 in DNA samples from 24 ovarian cancers, 9 cervical cancers, and 13 non-malignant gynecological diseases were determined respectively, using South blot method with probe PYNZ.22. Results:LOH on 17p13.3 was found in 12 of 24 (50.0%) ovarian cancers (including a borderline mucinous cystadenoma), 4of 9 (44.4%) cervical carcinomas, and 1 of 13 (7.7%) nonmalignant gynecological diseases, which was cervical intraepithelial neoplasm HI (CIN Ⅲ) (P＜0.01).Conclusion: These results show that LOH on 17p13.3 is associated with ovarian cancer and cervical cancer,suggesting that detection of LOH on 17p13.3 may be helpful to understand the molecular pathogenesis of ovarian cancer and cervical cancer.