Abstract Introduction Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi, remains an important cause of febrile illness in low- and middle-income countries (LMIC). However, the exact burden is difficult to estimate due to limitations in diagnosis and surveillance. Methods Samples from a representative cross-sectional household serosurvey in rural western Cambodia were used to estimate enteric fever seroincidence among children and young adults. Participants were enrolled between April 7 and December 10, 2023, and 529 samples from individuals aged 5-25 years were analysed. Using IgA and IgG responses to hemolysin E antigen and established models of antibody decay after infection, we estimated seroincidence, conveying the rate of new infection in the population. Participants were enrolled between April and December 2023, and 529 samples from individuals aged 5-25 years were analysed. Results The overall enteric fever seroincidence rate was 161.8/1,000 person-years (95%CI: 144.6, 181.0). Among children 5-15 years, it ranged between 149.5 (95%CI: 128.7, 173.7) and 239.0 (95%CI:169.2, 337.6) across districts. Seroincidence was numerically higher among children 5-15 years from households with unimproved drinking water sources or sanitation facilities, and districts with a higher proportion of households with unimproved WASH. Conclusion These findings potentially support the introduction of the typhoid conjugate vaccine in rural western Cambodia. However, additional data on the relative contribution of S. Typhi versus S. Paratyphi is needed. We also demonstrate seroincidence as an adjunctive valuable surveillance tool in LMICs where facility-based surveillance may be inadequate. Key questions What is already known on this topic Cambodia is estimated to have a high burden of enteric fever with a modelled incidence of 1.1/1,000 person-years among those under 20 years in 2023, but lacks population-level data. Existing estimates likely underestimate the burden because facility-based surveillance is affected by limitations on diagnosis sensitivity and healthcare access, and the modelled approach lacks country-specific incidence data. Validated antibody kinetics models using Hemolysin E (HlyE) antigen of Salmonella serovars Typhi and Paratyphi enable estimation of enteric fever seroincidence from cross-sectional serosurveys. What this study adds This study provides the first population-based estimates of enteric fever seroincidence in rural western Cambodia using HlyE antibody kinetics. Children 5-15 years showed high enteric fever seroincidence that potentially meets the WHO definition for a high-typhoid-incidence setting. Seroincidence varied geographically and by age, with higher seroincidence in districts with poor water, sanitation and hygiene (WASH) access, and the patterns suggest variations in S . Typhi and S . Paratyphi attribution. How this study might affect research, practice or policy Our findings indicate a substantially higher enteric fever burden in rural western Cambodia than previously reported. High seroincidence among children supports the consideration of the typhoid conjugate vaccine introduction, while highlighting the need for blood culture data to clarify S . Typhi and S . Paratyphi attribution to guide vaccination strategies better. Improving WASH access should also be prioritised to reduce transmission of both S . Typhi and S . Paratyphi. Seroincidence estimation from cross-sectional serosurveys offers a scalable approach for settings where blood culture surveillance is limited.