Breast cancer(BC)is the most common cancer among Japanese women aged 30-39 years. In recent years, the impact of oncofertility has become an important issue. In Gifu prefecture, the oncofertility network was established to provide information regarding cancer treatment and fertility preservation. We retrospectively analyzed 42 BC patients(mean age 34.5) who received treatment at Gifu University Hospital and consulted the oncofertility clinic between May 2013 and December 2023. The clinical stages were as follows:Stage 0 in 1 patient(2%), Stage Ⅰ in 14(33%), Stage Ⅱ in 23(56%), Stage Ⅲ in 3(7%), and Stage Ⅳ in 1(2%). The molecular subtypes were:Luminal A in 13 patients(31%), Luminal B in 14 (33%), Luminal/HER2 in 8(19%), HER2-enriched in 2(5%), and triple-negative BC in 5(12%). Fertility preservation was performed in 15 patients, including embryo cryopreservation in 10, oocyte cryopreservation in 4, and ovarian tissue cryopreservation in 1. Among them, 12 patients(80%)were either unmarried or married without children. Offering fertility preservation options and providing appropriate information are essential in supporting the treatment of young BC patients.