Krieger, NancySmith, KevinNaishadham, DeepaHartman, CathyBarbeau, Elizabeth M.Population health research on racial discrimination is hampered bya paucity of psychometrically validated instruments that can be feasiblyused in large-scale studies. We therefore sought to investigate the validityand reliability of a short self-report instrument, the ‘‘Experiences of Discrimination’’ (EOD) measure, based on a prior instrument used in the CoronaryArtery Risk Development in Young Adults (CARDIA) study. Studypar ticipants were drawn from a cohort of working class adults, age 25–64, based in the Greater Boston area, Massachusetts (USA). The main studya nalytic sample included 159 black, 249 Latino, and 208 white participants; the validation studyin cluded 98 African American and 110 Latino participants who completed a re-test survey two to four weeks after the initial survey. The main and validation survey instruments included the EOD and several single-item discrimination questions; the validation surveyal so included theWilliamsMajor and Everyday discrimination measures. Key findings indicated the EOD can be validlyand reliablyemploy ed. Scale reliabilitywas high, as demonstrated by confirmatory factor analysis, Cronbach’s alpha (0.74 or greater), and test–re-test reliabilitycoefficients (0.70). Structural equation modeling demonstrated the EOD had the highest correlation (r ¼ 0:79) with an underlying discrimination construct compared to other self-report discrimination measures employed. It was significantly associated with psychological distress and tended to be associated with cigarette smoking among blacks and Latinos, and it was not associated with social desirabilityin either group. By contrast, single-item measures were notablyless reliable and had low correlations with the multi-item measures. These results underscore the need for using validated, multi-item measures of experiences of racial discrimination and suggest the EOD maybe one such measure that can be validlyemploy ed with working class African Americans and Latino Americans.Health EquityStressSmoking & Tobacco UsestudiesRacial discriminationValidityReliabilityPsychometricBlackLatinoUSAArticle