We investigated the pre-operative and one-year post-operative health-related quality of life (HRQoL) outcome by using a Euroqol (EQ-5D) questionnaire in 230 patients who underwent surgery for lumbar spinal stenosis. Data were obtained from the National Swedish Registry for operations on the lumbar spine between 2001 and 2002. We analysed the pre- and postoperative quality of life data, age, gender, smoking habits, pain and walking ability. The relative differences were compared to a Swedish EQ-5D population survey. The mean age of the patients was 66 years, and there were 123 females (53%). Before the operation 62 (27%) of the patients could walk more than 500 m. One year after the operation 150 (65%) were able to walk 500 m or more. The mean EQ-5D score improved from 0.36 to 0.64, and the HRQoL improved in 184 (80%) of the patients. However, they did not reach the level reported by a matched population sample (mean difference 0.18). Women had lower pre- and post-operative EQ-5D scores than men. Severe low back pain was a predictor for a poor outcome.