Colorectal cancer (CRC) screening rates in Vietnamese Americans are lower than those in non-Hispanic whites. Consistent with our long-term goal of reducing morbidity and mortality caused by colorectal cancer, we propose to disseminate an evidence-based lay health worker (LHW) intervention supported by a media campaign (Media) to increase CRC screening in this poor and medically underserved population. We will use the Pathways Framework, Community-Based Participatory Research process, and Diffusion of Innovations Theory to guide our approach to the intervention, community participation, and dissemination. The specific aims of this study are to: 1) evaluate the effectiveness of a CRC LHW + Media intervention in increasing CRC screening among Vietnamese Americans aged 50 to 74 who have never had a CRC screening test, 2) identify predictors of CRC screening, and 3) evaluate the process of community participation. Following formative research using a cognitive testing approach to develop culturally and linguistically appropriate health education materials and survey instruments, we will conduct a cluster randomized trial among Vietnamese Americans aged 50-74 in Santa Clara County California, who have never had a CRC screening test prior to recruitment. We will follow two longitudinal cohorts among whom we will conduct a pre-intervention survey of participants'knowledge, intention, and behavior as regards CRC screening;implement CRC screening educational sessions in an experimental group and nutrition educational sessions in a comparison group;and conduct a post-intervention survey. Each of the two cohorts will include 150 men and 150 women to have a total sample size of 600. The media intervention component will distribute Vietnamese-language health education materials through print and electronic media. We will evaluate the effectiveness of the intervention by comparing the frequency of screening using pre- and post-intervention surveys. To test our primary hypothesis regarding the effects of the intervention on screening activity, we will use Z-tests. We will also employ logistic regression models to test the effects of the intervention and to identify predictors for CRC screening. In addition, we will conduct process evaluation of the intervention and community participation. If this intervention is found to be effective, this LHW model could be applied in health promotion programs to further reduce disparities in CRC screening in Vietnamese Americans and evaluated in other behavioral objectives and settings to reduce health disparities in other poor and underserved populations. PUBLIC HEALTH RELEVANCE: Colorectal cancer (CRC) screening rates in Vietnamese Americans are lower than those in non-Hispanic whites. Relative to non-Hispanic whites, Vietnamese Americans are both poorer and less well medically served and have special language and cultural issues related to cancer screening that cannot be addressed though interventions aimed at the general population. Consistent with our long-term goal of reducing morbidity and mortality caused by colorectal cancer, we propose to disseminate an evidence-based lay health worker (LHW) intervention supported by a media campaign (Media) to increase CRC screening in this poor and medically underserved population. If this intervention is found to be effective, it could be applied in other health promotion programs throughout the United States to further reduce disparities in CRC screening in Vietnamese Americans. In addition, this LHW model could be evaluated in other populations, such as other racial and ethnic, poor, or immigrant communities;in other behavioral objectives, such as other forms of cancer, cardiovascular health, or tobacco, diabetes and obesity control;and in other settings, such as community health clinics and hospitals. Public Health Relevance: Colorectal cancer (CRC) screening rates in Vietnamese Americans are lower than those in non-Hispanic whites. Relative to non-Hispanic whites, Vietnamese Americans are both poorer and less well medically served and have special language and cultural issues related to cancer screening that cannot be addressed though interventions aimed at the general population. Consistent with our long-term goal of reducing morbidity and mortality caused by colorectal cancer, we propose to disseminate an evidence-based lay health worker (LHW) intervention supported by a media campaign (Media) to increase CRC screening in this poor and medically underserved population. If this intervention is found to be effective, it could be applied in other health promotion programs throughout the United States to further reduce disparities in CRC screening in Vietnamese Americans. In addition, this LHW model could be evaluated in other populations, such as other racial and ethnic, poor, or immigrant communities;in other behavioral objectives, such as other forms of cancer, cardiovascular health, or tobacco, diabetes and obesity control;and in other settings, such as community health clinics and hospitals.