The Session Rating Scale 3.0 (SRS 3.0) is an ultra-brief measure of the therapeutic alliance, frequently used to provide feedback to the clinician during the therapeutic process (Prescott et al. [2017]. "Feedback-informed treatment in clinical practice. Reaching for excellence." American Psychological Association (APA). http://www.apa.org/pubs/books/4317449.aspx). This study describes the psychometric properties of the SRS 3.0 in a Spanish clinical sample of 165 adult psychotherapy patients from different primary care centres of Barcelona (Spain). Results show the measure has good reliability and good convergent and predictive validity. The results are consistent with the findings from studies done in other countries. In summary, the instrument appears to be a valid and reliable tool for monitoring therapeutic alliance during the course of psychotherapy with Spanish-speaking patients. Additional research with the SRS 3.0 in Spanish could provide more evidence of its psychometric properties.