The 2005 Youth Risk Behavior Survey (YRBS) report is a continuation of the surveillance and reporting system for adolescent risk behaviors developed by the Division of Adolescent and School Health, National Center for Chronic Disease Prevention and Health Promotion, U.S. Centers for Disease Control and Prevention (CDC). The purpose of the YRBS is to assist educators and health professionals in determining the prevalence of the aforementioned health-risk behaviors among youth. This report describes the results of the survey and the methods used to conduct the survey. The results will be used to focus the continuing development of statewide comprehensive health education and to reduce those health behaviors that place Montana youth at risk. Survey results for each of the risk factors are presented in two parts: (1) An overview of the risk factor as it applies to Montana youth; and (2) Highlights of the results of the 2005 YRBS for American Indian students on Montana Reservations. Results of the 2005 Montana Youth Risk Behavior Survey for American Indian students on Montana Reservations indicate that although progress has been made over the past several years in decreasing risk from undesirable behaviors, Montana health, education, and social professionals need to continue to focus on those primary risk behaviors that cause the greatest amount of mortality, morbidity, and social problems among Montana youth. Appended are: (1) Frequency Distributions; (2) Referenced Figures; and (3) Additional Charts. (Contains 15 figures, 20 charts, and a list of 11 resources.) [Report prepared for the Montana Office of Public Instruction, Division of Health Enhancement, HIV/STD Education Program by Dodge Data Systems, Inc.]