The Yale-Brown Obsessive-Compulsive Scale, Second Edition (Y-BOCS-II) is an evidence-based clinician-rated measure for assessing the presence and severity of obsessive-compulsive symptoms. The Spanish version of the YBOCS-II has not yet been validated. The present study examines the psychometric properties of the Spanish YBOCS-II (Spanish-Y-BOCS-II) in adults with obsessive-compulsive disorder (OCD) who are of Hispanic/Latino ancestry. The Spanish-Y-BOCS-II was administered to 1805 adults with OCD. Participants also completed a battery of measures assessing OCD, depression, and anxiety symptoms. The internal consistency for the Symptom Checklist (Kuder-Richardson-20=0.92), Obsession Severity (alpha=0.87), Compulsion Severity (alpha=0.86), and Total Severity (alpha=0.92) were high. The inter-rater reliability for the Severity Scale (intraclass correlations=0.98) was excellent. Confirmatory factor analyses showed a marginally acceptable fit with the Obsessions and Compulsions two-factor model; subsequent exploratory factor analysis revealed a one-factor solution consistent with a Total score including all items. Satisfactory construct validity was observed, supported by the strong correlations with other measures of obsessive-compulsive symptom severity and moderate correlations with measures of depression and anxiety symptoms. Overall, the Spanish-Y-BOCS-II demonstrates acceptable reliability and validity properties.