Negative stereotypes about older workers can result in different types of age discrimination. The aim of this study was to run a transcultural adaptation and validation of the Nordic Age Discrimination Scale (NADS) into Spanish. Three independent samples of Chilean (N = 301), Colombian (N = 150), and Spanish (N = 209) workers over the age of 45, from different sectors and professional categories, answered a questionnaire including the NADS scale, measures of perceptions of inequality, workplace harassment and several scales related to outcome variables to test criterion and construct validity. The reliability index for the NADS was .85, a similar value for both Cronbach's alpha (α) and McDonald's omega (ω). CFA by country suggest good fit of this single-dimension structure in a final version of 5 items, and it presents scalar invariance; using the modification indices, partial invariance is achieved at the level of the variance of the errors. Both criterion and construct validity were verified, with strong evidence for criterion validity, and moderate results for construct validity. Therefore, the Spanish version of NADS had a single-dimension structure and adequate psychometric properties being a useful tool in measuring perceptions of age discrimination in different countries.