The Community Youth Activity Program (CYAP) was the first Center for Substance Abuse Prevention grantee demonstration project with a community prevention emphasis mandated by Congress under the Anti-Drug Abuse Act of 1988. One of the goals of the national evaluation of the CYAP, which expanded to 31 state grantees, was to establish a baseline of information on the development and effectiveness of the program's strategies for high-risk youth. To address this goal, the nature of the population served by CYAP was studied, including their knowledge, attitudes, and behavior. A Knowledge, Attitudes, and Behavior (KAB) instrument was developed to measure preprogram, immediate postprogram, and delayed postprogram responses of 1,797 youth aged 9 to 21 years from 14 states. Alcohol and other drug (AOD) knowledge, attitudes, and behavior do not appear related to ethnicity. When the five factors of risk, protection, AOD knowledge, attitudes, and behavior are analyzed separately, it becomes evident that males demonstrate more risk behavior than do females. African Americans and Native Americans are the most protected among the high-risk groups, probably because of participation in religious and recreational activities. The protection factor level is directly related to AOD knowledge and behavior, and inversely related to AOD behavior. Implications for AOD prevention programs are discussed. Six tables and two figures present study findings. The 38-item KAB instrument is included. (SLD)