Over the last four decades, assessments of health risks based on estimated radiation doses received by the public have been completed for all major U.S. nuclear testing sites and nuclear fuel cycle facilities in the U.S. except for the Trinity test. This research plan is for a radiationrelated cancer risk projection study for the residents of the state of New Mexico (NM) potentially exposed to radioactive fallout from the Trinity nuclear test conducted in 1945. Data to be collected on diet and lifestyle from the three main ethnic groups in NM (white, Hispanic, and Native American) via focus groups and key informant interviews will be used to derive means and ranges of exposure-related parameters for a dose assessment and risk projection. As preliminary work to this proposal, in 2014 we conducted a pilot study to obtain information from 9 key informants (maximum number allowed under OMB regulations prior to clearance) determined that the elders could recall the relevant time period and relevant lifestyle practices. This work established that it is possible to: 1) locate elderly representative of the ethnic groups, 2) assemble groups of members of tribal, a n d Hispanic/Latino communities in New Mexico who were alive in 1945 at the time of the test to participate in focus groups, and 3) obtain lifestyle and diet information to be used for refining focus group interviewing tools. Due to the successful completion of the pilot phase, here we are proposing a second phase to collect data, on a larger scale, via focus group and individual interviews, on lifestyle and diet from up to 150 Native American, Hispanic/Latino, and non-Hispanic white participants living in New Mexico who were alive at the time of the Trinity detonation (currently greater than or equal to 70 years old). The data collected in the proposed study will allows us to estimate exposure-related parameter values that can be used in fallout dose assessment models to estimate external and internal radiation doses to representative persons in all counties in New Mexico by ethnicity, gender, and age. Those doses will be used with published risk models and coupled with literature-derived parameters on risk/unit dose to project the excess cancers (per 1,000 persons within each strata) expected. Endpoints are leukemia, thyroid cancer, stomach cancer, and colon cancer.