With the advent of cancer therapy, increasing numbers of cancer patients are achieving long term survival. Impaired ovarian function after radiation and/or anticancer agent therapy has been reported in several studies. The recent success in the polychemotherapy in cancer patients poses a new dilemma for the specialists who strive to improve quality of life while preserving fertility, especially as there is an increase in neither the risk of congenital malformation nor spontaneous abortion with previous chemotherapy. Gonadotropin-releasing hormone (GnRH) analogues (GnRHa) act to protect the gonads during radiation and/or chemotherapy by preferentially steering cells into cell cycle arrest with a decline in responsibility to the chemotherapy and radiation.  In women who wish to maintain potential fertility, GnRHa therapy is successful in preventing the most critical postoperative complication, gonadal damage. GnRHa cotreatment can also prevent the bone demineralization and osteoporosis associated with hypoestrogenism and ovarian failure.