Abstract The Experiences in Close Relationships (Brennan et al, Attachment theory and close relationships, 1998) questionnaire is one of the most widely used measures of adult romantic attachment. Despite the advantages of the ECR, the length of this measure may discourage its use in clinical and research contexts. Consequently, the goal of this study was to develop a brief Spanish version of the ECR questionnaire and to examine its psychometric properties when administered to six different Spanish-speaking samples from Chile. Confirmatory factor analyses replicated the twodimensional structure of the ECR and its invariance across gender. Results also supported the reliability and concurrent validity of our brief Spanish version of the ECR (i.e., Spanish ECR-12), by its association with measures of emotion regulation, dyadic empathy, psychological distress and well-being, and relationship satisfaction. The Spanish ECR-12 can be used by researchers and clinical professionals as an abridged measure of adult attachment.