OBJECTIVES: To assess the clinimetric properties of the Spanish version of the Self-Esteem And Relationship (SEAR) questionnaire to be used in Spain with patients with ED. METHODS: The SEAR questionnaire comprises 14 items divided into two domains: Sexual Relationship (8 items) and Confidence (6 items), the latter comprising Self-Esteem (4 items) and Overall Relationship (2 items). The USA-English-version of SEAR questionnaire was adapted linguistically into Spanish by using forward and back translation methods and a conceptual equivalence approach. The SEAR questionnaire was administered to a group of patients with ED (IIEF<26) seven days before starting treatment and at baseline and after three months of treatment (group A), and to a group of healthy control subjects (IIEF≥26) (group B) in a single visit. SF-12 and HAD scales were also administered. RESULTS: Out of 831 recruited subjects (n=732, group A; n=99, group B), 559 subjects were included as evaluable for validation analysis (n=504, group A; n=55, group B). The percentage of patients without response was < 5% for all domains. Cronbach's Alpha coefficient was 0.92 and 0.86 in groups A and B. The SEAR questionnaire discriminated between patients and controls (area under curve =0.999) and groups of patients by severity of ED (Kruskall-Wallis test: p<0.0001). Correlation was high with Erectile Function scale of IIEF (r=0.69) and moderate with HAD (r=-0.41) and SF-12 Mental Health (r=0.38). The SEAR questionnaire also showed responsiveness with improvement in scores from start to end of treatment (Mann-Whitney-Wilcoxon test: p<0.0001). CONCLUSIONS: The SEAR questionnaire showed adequate feasibility, reliability, validity and responsiveness for its use for measuring the emotional tension and relationship difficulties associated with erectile dysfunction.