The Outcome Rating Scale (ORS) is an ultra-brief measure of well-being designed to track outcome in psychotherapy. This research studied the psychometric properties of the ORS in a Spanish clinical sample. One-hundred and sixty-five adult participants from different primary care centers of the city of Barcelona were recruited. The psychometric properties of the ORS in the sample were explored and described, comparing them to the properties of other instruments already validated in Spain. Our results showed good reliability (α = .91 [.88, .93]; α = .96; test re-test correlations from .61 to .84), good validity (convergent validity correlations with distress and symptoms measures from –.32 to –.76), and good sensitivity to change (pre-post comparison through Wilcoxon signed-rank test, Mdnpre = 31.0, Mdnpost = 19.6, z = –7.38, p < .05, r = .42). These results are consistent with previous findings in other countries. We conclude suggesting that the instrument can be applied to monitor outcome in psychotherapy and to test the effectiveness of treatments imparted with Spanish speaking clients. However, further research with the ORS in Spanish could provide more evidence of its psychometric properties.