Cerebral palsy is a pathological condition whose prevention and treatment have been immensely studied by experts in perinatal medicine and pediatric neurology. Despite this, it is still one of the main concerns nowadays in many countries, not only for scientific reasons but for legal ones also. For instance, in Japan, an increase in lawsuits relating to cerebral palsy was observed more than a decade ago, after healthcare resources in perinatal medicine had increasingly shrunk and had become fragile under the growing burden for physicians and midwives to provide advanced treatment, emergent care, high-risk treatment, and so on. Young physicians did not specialize in obstetrics because of the increased burden, which gave rise to a vicious cycle of shrinking resources in perinatal medicine. To address this issue, the Japan Obstetric Compensation System for Cerebral Palsy (JOCS-CP) was urgently introduced in 2009 to investigate, develop preventive measures, and award monetary compensation on a no-fault basis, with the Japan Council for Quality Health Care (JQ) as its operating organization (Fig. 33.1). It has so far produced annual reports on the prevention of cerebral palsy for nine consecutive years including numerical data and specific themes relating to the occurrence and prevention of cerebral palsy. The success of the system is a good reference for responding to adverse events which may happen in and have a vast impact on perinatal care. Therefore, this chapter focuses on cerebral palsy with primary reference to materials published by the JOCS-CP in the field of perinatal medicine. The aim of this chapter is to learn about the issues mentioned above and to discuss the significance and impact of introducing a nationwide system like the JOCS-CP. It describes knowledge and idea to questions of “Why cerebral palsy is highlighted among adverse event in obstetrics?”, “How the no-fault compensation/investigation/prevention system could be introduced?”, “What has been achieved by the system?”, and “How cerebral palsy is prevented?”.