Abstract Background The prevalence of major low anterior resection syndrome (LARS) after rectal cancer surgery varies from 17·8 to 56·0 per cent, but data from high-quality studies are sparse. The aim of this study was to determine the prevalence of LARS and its association with quality of life (QoL) in a large, well defined, population-based cohort. Methods This was a population-based study that included all patients who had curative rectal cancer surgery with total or partial mesorectal excision in Stockholm County in Sweden between 2007 and 2013. Patients without a remaining stoma, free from cancer and alive in April 2017 were eligible for the study. The LARS score questionnaire, EORTC QLQ-C30 and Cleveland Clinic Florida Fecal Incontinence score were used as outcome measures. Adjusted mean scores (and differences) of EORTC QLQ-C30 for LARS groups were calculated using repeated measures ANCOVA regression models while adjusting for predefined confounders. Results In total, 481 patients (82·6 per cent response rate) were included in the analysis. Mean follow-up time was 6·7 (range 3·4–11·0) years after surgery. The prevalence of LARS was 77·4 per cent (370 of 478 patients), with 53·1 per cent (254 of 478) experiencing major LARS. Patients with major LARS reported worse on all EORTC QLQ-C30 subscales (except for financial difficulties) than patients without LARS. A higher mean LARS score was associated with a greater impact on bowel-related QoL. Conclusion After anterior resection for rectal cancer, the majority of patients suffer from major LARS with a negative impact on QoL.