Clinical studies indicate that functional somatic disorder (FSD), a condition characterized by persistent physical symptoms not attributable to other physical or mental conditions, imposes a high socioeconomic burden, but high-quality studies on its impact on welfare benefit utilization in the general population are lacking. This study investigated the use of sickness benefit, unemployment benefit, and disability pension for individuals with FSD using nationwide Danish registers. This study included 9656 adults from the DanFunD study. FSD were identified via self-reported questionnaires and diagnostic interviews. Data on welfare benefits were sourced from The Danish Register for Evaluation of Marginalization, counting the mean number of weeks per year over 10 years before and 4 years after the DanFunD study. Analyses used sex- and age-adjusted regression with non-parametric bootstrap resampling (10,000 repetitions). Compared to those without FSD, individuals with FSD received an annual average of 3.9 (95 % CI: 3.3-4.4) more weeks of sickness benefit, 1.3 (95 % CI: 1.0-1.6) more weeks of unemployment benefit, and 3.8 (95 % CI: 3.2-4.5) more weeks of disability pension in the 10 years before DanFunD. This pattern persisted in the 4 years after DanFunD and for those diagnosed by interviews. Individuals with questionnaire-defined FSD had higher welfare benefit use than individuals with other severe physical diseases. Individuals with FSD use welfare benefits significantly more than those without FSD and those with other severe physical diseases. This study highlights FSD as a disabling condition with a substantial individual and societal impact, emphasizing the need for timely diagnosis and treatment. Trial registration:ClinicalTrials.gov Identifier: NCT05611606.