Background: In settings without aetiologic testing for sexually transmitted infections (STIs), programmes rely on STI symptom data to inform priorities. To evaluate whether self-reported STI symptoms in household surveys consistently represent the STI burden, we compared symptomatic infection rates between survey self-reporting and health facility case reporting in Malawi. Methods: We analysed self-reported symptoms and treatment seeking in the past year among sexually active adults from four Malawi Demographic and Health Surveys between 2000-2015. Bayesian mixed-effects models were used to estimate temporal trends, spatial variation, and sociodemographic determinants. Survey reporting was compared with health facility syndromic diagnoses between 2014-2021. Results: In surveys, 11.0% (95% CI:10.7-11.4%) of adults reported STI or STI-related symptoms in the last year, of whom 54.2% (52.8-55.7%) sought treatment. In facilities, the mean annual symptomatic case diagnosis rate was 3.3%. Survey-reported treatment in the last year was 3.8% (95% CrI:2.3-6.1%) for genital ulcer, 3.8% (2.0-6.7%) for vaginal discharge, and 2.6% (1.2-4.7%) for urethral discharge. Mean annual diagnosis rates at facilities were 0.5% for genital ulcer, 2.2% for vaginal discharge, and 2.0% for urethral discharge. Both data sources indicated a higher burden of symptoms among women, individuals above 25 years, and in Southern Malawi. Conclusion: Survey and facility case reports indicated similar spatial and demographic patterns of STI symptom burden and care seeking, but implied large differences in the magnitude and relative burden of symptoms, particularly genital ulcer, which could affect programme priorities. Targeted aetiologic surveillance would improve interpretation of these data to enable more comprehensive STI surveillance
