<P>Background: Gallstone surgery is one of the most common surgical procedures in Sweden. In order to assess the impact on quality of life from gallstone surgery, a reliable instrument with sufficient responsiveness is required.<P>Materials and methods: The Swedish Register for Gallstone Surgery and ERCP (GallRiks) was founded in May 2005, with the aim of registering indications, complications, results and quality of life outcome of gallstone surgery. By the end of 2007, the register covered 56 hospitals. Altogether 8804 cholecystectomies and 5042 ERCP have been registered. As a pilot study SF-36 has been filled in prior to surgery and 6-9 months postoperatively at some of the units. Four of these hospitals were chosen for this study. Expected SF-36 scores were determined from the age- and gender-matched population. Linear Multivariate regression analysis was performed to assess which factors had the greatest impact on the responsiveness.<P><P> Results: Out of 206 operated patients, 148 responded to the SF-36 questionnaire prior to and 6-9 months post surgery, yielding a response rate of 72% (= 148/206). Standardized response means ranged from 0.20 to 0.82 for the SF-36 sub scores. The highest responsiveness was seen for bodily pain. Prior to surgery, all sub scores were significantly lower than in the general population (all p<0.05). Six months after surgery, all sub scores were equal to or higher than the expected except for general health (p<0.05). Low age, laparoscopic surgery and cholecystitis, pancreatitis or jaundice as indication for surgery were found to be associated with significantly higher improvement of physical component summary in multivariate linear regression analysis (all p<0.05).<P> Conclusion: SF-36 is a useful instrument for measuring the impact of gallstone surgery on quality of life. Good quality requires careful consideration of indication for surgery as well as use of adequate technique.