OBJECTIVES: The study aims to document the psychometric characteristics of the Spanish translation of two questionnaires: RDQ to evaluate GERD symptoms and GIS to evaluate impact of symptoms in patients´ daily life. METHODS: A psychometric validation study to evaluate two self-administered questionnaires in 300 patients with reflux symptoms. Each investigator conducted the study on two consultations (basal/2 weeks visits) in one patient with GERD diagnosis and no predictable changes in their health status in the following 16 days (reliability group) and 4 new patients to be treated with a known efficient treatment (sensibility group). RESULTS: A total of 281 evaluable patients were analysed; mean age was 55,6 years (95%CI: 53.9-57.3) and 48% were male. Factibility: More than 80% of patients complete the RDQ (100% Visit 1 and 99.6% Visit 2) and 99.3% GIS questionnaire (both visits). Only 0.71% patients left one missing item in the RDQ and 1.07% in the GIS questionnaire. Validity: RDQ and GIS questionnaires are able to discriminate frequency and sensibility of symptoms (p<0.0001). Reliability of internal consistence: Both questionnaires have a good internal consistence. RDQ showed an alpha value (Cronbach) ≥ 0.70 and CCI ≥ 0.60 in all domains. GIS questionnaire had an alpha value ≥ 0.69 and CCI ≥ 0.45 in all domains. Sensibility to change (sensibility group): Both questionnaires show a high sensibility to the patient recovery. When the either the physician or the patient found an improvement in the health at two weeks, the differences in the scores were always statistically significant (p<0.0001). CONCLUSIONS: RDQ and GIS questionnaires have satisfactory reliability, validity and sensibility to change. Both tools are easy to use and suitable to evaluate the impact and the severity of reflux symptoms in GERD patients.