The objective of this study was to evaluate the reliability and validity of the Gastrointestinal Symptom Rating Scale (GSRS) in US patients with gastroesophageal reflux disease (GERD). Five hundred and sixteen adults with predominant heartburn symptoms of GERD were recruited from gastroenterologist and family physician practices and treated with 6 weeks of 150mg ranitidine twice daily to identify poorly responsive symptomatic GERD. The GSRS, the Medical Outcomes Study Short Form-36 (SF-36) Health Survey and the Psychological General Well-being (PGWB) scale were administered at baseline and after 6 weeks of treatment. Reported ratings of GERD-related symptoms from physician and patient diaries were measured. The GSRS contains five scales: reflux syndrome, abdominal pain, constipation syndrome, diarrhoea syndrome and indigestion syndrome. The internal consistency reliabilities for the GSRS scales ranged from 0.61 to 0.83 and the intraclass correlation coefficients ranged from 0.42 to 0.60. The GSRS scale scores were correlated with the SF-36 and PGWB scales and with the number and severity of heartburn symptoms. Patients with two or three clinician-rated GERD-related symptoms reported worse GSRS scale scores compared with patients with fewer symptoms (p < 0.0001).="" statistically="" significant="" differences="" in="" the="" mean="" gsrs="" scale="" scores="" were="" observed="" between="" treatment="" responders="" and="" non-responders="" (p="">< 0.0001)="" and="" patients="" showing="" a="" response="" to="" treatment="" had="" larger="" mean="" changes="" in="" their="" gsrs="" scales="" than="" patients="" not="" showing="" a="" response="" to="" treatment="" (p="">< 0.0001).="" the="" standardized="" response="" means="" ranged="" from="" 0.42="" to="" 1.43="" for="" the="" gsrs="" scale="" scores.="" it="" was="" concluded="" that="" the="" gsrs="" is="" a="" brief,="" fairly="" comprehensive="" assessment="" of="" common="" gastrointestinal="" symptoms.="" the="" gsrs="" has="" good="" reliability="" and="" construct="" validity="" and="" the="" gsrs="" scales="" discriminate="" by="" gerd="" symptom="" severity="" and="" are="" responsive="" to="" treatment.="" the="" gsrs="" is="" a="" useful="" patient-rated="" symptom="" scale="" for="" evaluating="" the="" outcomes="" of="" treatment="" for="">