Objective: To address the relation among pelvic inflammatory disease (PID), genetic vulnerability and ovarian cancer (OC) risk, we assessed the association between PID and OC risk, alongside the interplay with germline homologous recombination repair (gHR) mutation, utilizing the UK Biobank. Methods: We conducted a prospective cohort study in the UK Biobank by tracking OC incidences between individuals with and without a PID history. Identification of gHR mutations (BRCA1, BRCA2, RAD51C, RAD51D, BRIP1) carriers were accomplished through paired whole-exome sequencing data. We used Cox’s regression models to evaluate the hazard ratios (HRs) for OC risks under PID. Results: In the large prospective cohort study, the adjusted HR for OC in patients with PID was 1.45 (95% confidence interval [CI]=0.90, 2.32) compared with those with non-PID.Intriguingly, age-stratified analysis unveiled a positive association between PID history and OC risk in those aged under 55 years (HR=1.92; 95% CI=1.02, 3.63). Moreover, individuals aged younger than 55 years harboring both a history of PID and gHR mutations exhibited the highest risk of OC (HR=7.40; 95% CI=1.03, 53.10). Conclusion An association between PID and OC risk emerged, notably in the subgroup aged younger than 55 years old. Individuals with both a PID history and gHR mutations exhibited the highest risk of OC. These findings imply PID as a potential precursor for OC, underscoring the importance of early intervention, particularly in the younger population with gHR mutations.