Rad52 encodes a protein which is required for recombinational repair of double-strand breaks. It is also associated with breast cancer predisposition genes BRCA1 and BRCA2. Mutations in the genes Rad51 or Rad52 result in severe defects in genetic recombination and the repair of double-strand DNA breaks. In order to examine if Rad52 mutations might be involved in sporadic ovarian cancer, we analyzed two stop mutations (Ser346ter and Tyr415ter) in 142 Austrian ovarian carcinoma patients and 128 healthy volunteers. In addition, we analyzed these two mutations in 105 breast/ovarian cancer families (160 members) to examine if the mutations in Rad52 are associated with the occurrence of cancer and with mutations in the BRCA1 and BRCA2 genes. Our results show that these two mutations are rare in all three groups examined. There are no statistically significant differences in the frequencies of the Rad52 mutations between the control group and sporadic ovarian cancer patients and between the control groups and familial breast/ovarian cancer patients, indicating that these two mutations of the Rad52 do not play a major role in the initiation of sporadic ovarian carcinoma and familial breast/ovarian cancer.