To monitor priority health-risk behaviors among youth and young adults, the Centers for Disease Control and Prevention developed the Youth Risk Behavior Surveillance System (YRBSS). The YRBSS includes national, state, territory, and local school-based surveys of high school students in grades 9-12. In addition, some states, territories, and cities conduct a school-based Youth Risk Behavior Survey (YRBS) among middle school students. In 2003, five Pacific Island territories conducted a YRBS among students in grades 9-12 and three territories conducted a YRBS among students in grades 6-8. Adults and adolescents living in the Pacific Island territories encounter both the communicable diseases found in developing countries and the chronic diseases associated with developed countries. Overall, the leading causes of death for the region are coronary heart disease, cancer, suicide, and accidents. Health issues among adults include tobacco and substance abuse, tuberculosis, and sexually transmitted diseases. In addition, the World Health Organization reports a high prevalence of obesity (up to 70% in some areas) among adults. Consequently, diabetes is an increasingly prevalent public health problem in the Pacific Island region. Among adolescents, substantial morbidity, mortality, and social problems result from suicide, substance abuse, violence, pregnancy, and sexually transmitted diseases. This report summarizes data from three territories (Commonwealth of the Northern Mariana Islands, Republic of the Marshall Islands, and Republic of Palau) with weighted high school data and from two territories (Commonwealth of the Northern Mariana Islands and Republic of Palau) with weighted middle school data. Two additional territories (American Samoa and Guam) conducted a YRBS among high school students but did not obtain weighted data, and one territory (Guam) conducted a YRBS among middle school students but did not obtain weighted data. All the surveys were conducted during spring 2003. Data from territories with unweighted data are not included in this report. (Contains 136 tables.)