Objective: To assess the psychometric properties ofvalidity and reliability of the Kessler-10 Psychological Distress Scale (K-10) in a sample of Spanish older adults. Method: An observational, analytical cross-sectional study was conducted for instrument validation between May and June 2022. The sample consisted of 887 individuals aged 65 and over. To assess the psychometric properties, reliability was evaluated using standardized Cronbach's alpha and McDonald's omega coefficients, while construct validity was examined through exploratory and confirmatory factor analyses. Convergent validity was assessed using Pearson's correlation coefficients (using the 5-item Geriatric Depression Scale [GDS-5]). The unidimensional factor structure proposed in the original development of the scale was analyzed. Results: Exploratory factor analysis yielded a one-factor structure explaining 67.48%of the total variance. Confirmatory factor analysis confirmed the unidimensional structure of the scale [weighted least squares mean and variance adjusted, WLSMV-x2 (df= 35) = 125.083; comparative fit index, CFI = 0.951; Tucker-Lewis index, TLI= 0.938; root mean square error of approximation, RMSEA = 0.066 (confidence interval: 0.052-0.081)]. The correlation with GDS-5 scores supported the existence of convergent validity (r = 0.599; p < 0.001). Adequate reliability coefficients were obtained for the general factor (a = 0.944; o = 0.945). Conclusions: The K-10 scale showed adequate levels of validity and reliability in the sample. The results obtained suggest that it is a suitable instrument for assessing non-specific psychological distress in older adults. Its brevity and ease of administration make the scale particularly suitable for epidemiological research and/or screening. (c) 2025 SESPAS. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).