Objective: The objective of this paper is to assess the reliability and validity of the Spanish translation of the Clinical Outcomes in Routine Evaluation – Outcome Measure, a 34-item selfreport questionnaire that measures the client’s status in the domains of Subjective well-being, Problems/Symptoms, Life functioning, and Risk. Method: Six hundred and forty-four adult participants were included in two samples: the clinical sample (n=192) from different mental health and primary care centers; and the nonclinical sample (n=452), which included a student and a community sample. Results: The questionnaire showed good acceptability and internal consistency, appropriate test–retest reliability, and acceptable convergent validity. Strong differentiation between clinical and nonclinical samples was found. As expected, the Risk domain had different characteristics than other domains, but all findings were comparable with the UK referential data. Cutoff scores were calculated for clinical significant change assessment. Conclusion: The Spanish version of the Clinical Outcomes in Routine Evaluation – Outcome Measure showed acceptable psychometric properties, providing support for using the questionnaire for monitoring the progress of Spanish-speaking psychotherapy clients.