Mutated BRCA1/2 genes have been identified as causative genes for ovarian cancer, and it has been reported that 10%–20% of all epithelial ovarian cancers have a BRCA mutation. As novel treatment drugs utilizing this BRCA gene mutation, significant attention has been paid to adenine dinucleotide poly (ADP-ribose) polymerase inhibitors. Among them, olaparib has been reported to be useful in patients with a BRCA mutation in Study 19 and SOLO-2 trials. It is important to establish a system for genetic counseling and to perform BRCA gene testing in patients with ovarian cancer. For patients with BRCA -mutated advanced cancer, if adequate response to chemotherapy has been achieved, olaparib is recommended as maintenance therapy for both advanced and recurrent cases. For patients without BRCA gene mutation, bevacizumab combined with chemotherapy or as maintenance therapy is also an option.