This study attempts to adapt and validate the Spanish version of The Clinical Outcomes in Routine Evaluation—Outcome Measure CORE-OM questionnaire for Colombian and Peruvian populations. A linguistic and cultural adaptation of the CORE-OM Spanish version was created via cognitive interviews of potential users (Colombians n=28; Peruvians n=8). Then the questionnaire was applied along with the SOS and OQ-45 tests to 270 participants, divided in clinical (n=60), and non-clinical (n=210) samples, from three Colombian cities and one city in Peru. Some students made a retest application (n=26) 15 to 30 days after the first one. The CFA conducted showed a four-factor structure (X2/df=2.09; RMSEA=0.064; RMR=.069) that included well-being, problems/symptoms, general functioning, and risk. The Spanish version of CORE-OM showed excellent acceptability (96%; omission rate 0.14%), good internal consistency (a >.70 in most of the scales and samples), acceptable test-retest reliability (Spearman rho>0.70; p<.001) and convergent validity (all domains r >. 4; p < 0.01, except subjective well-being) in both populations. Significant differences were found in the scores between the clinical and non-clinical sample; although, the clinical sample presented higher scores. These results validate the 1-point cut-off score of between clinical and non-clinical populations. © 2021 by the Author(s);. All Rights Reserved.