Since after 2006 when the first edition of practice guidelines for gynecologic oncologic cancer treatment was released, the Korean Society of Gynecologic Oncology (KSGO) has published the following editions on a regular basis to suggest the best possible standard care considering updated scientific evidence as well as medical environment including insurance coverage. The Guidelines Revision Committee was summoned to revise the second edition of KSGO practice guidelines, which was published in July 2010, and develop the third edition. The current guidelines cover strategies for diagnosis and treatment of primary and recurrent ovarian cancer. In this edition, we introduced an advanced format based on evidence-based medicine, collecting up-to-date data mainly from MEDLINE, EMBASE, and Cochrane Library CENTRAL, and conducting a meta-analysis with systematic review. Eight key questions were raised by the committee members. For every key question, recommendations were developed by the consensus meetings and provided with evidence level and strength of the recommendation.