Some published evidence has revealed that the dendritic cells can interact with pathogens that exist in the inner foreskin. This information provides a new vision that pathogens could play a role through the redundant prepuce; numerous studies have failed to ifnd pathogens in prostates of patients who had chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS). However, no studies have reported an association between foreskin length and CP/CPPS. Hence, we conducted a retrospective case?control study of clinical data from 322 CP/CPPS patients(case group) and 341 nonCP/CPPS patients(control group). Demographic characteristics, lifestyle factors, and foreskin lengths were collected and analyzed. Multivariate logistic regression was adopted to calculate the odds of foreskin length for CP/CPPS. According to the multivariate logistic regression results, when the foreskin length covered up more than half of the glans penis, the odds for CP/CPPS were higher with an increased foreskin(odds ratio(OR): 1.66, 95% conifdence interval(CI): 1.04–2.66). In comparison, when the glans penis was completely covered by the foreskin, the OR value increased to 1.86(95% CI, 1.2–2.88). The study results showed an association between foreskin length and the odds of CP/CPPS. When the foreskin length covered up more than half of the glans penis, there were greater odds for CP/CPPS. This possible mechanism might result from interaction between pathogens and DCs in the inner foreskin, consequently activating T?cells to mediate allergic inlfammation in the prostate and producing the autoimmunizations causing CP/CPPS.