Study ObjectiveTo evaluate the prevalence of chronic endometritis (CE) among fertile and infertile women who underwent hysteroscopic polypectomy.DesignA retrospective cohort study.SettingUniversity-affiliated tertiary hospital.PatientsA total of 277 women who underwent hysteroscopic polypectomy in the period from 2015 to 2018.InterventionsEndometrial polyp samples were obtained after hysteroscopy for histopathologic analysis using hematoxylin-eosin and immunohistochemistry staining with CD138 antibodies for plasma cell detection. All infertile women diagnosed with CE were treated with oral doxycycline 100 mg twice daily for 14 days before infertility treatment.Measurements and Main ResultsThe prevalence of CE in infertile women (n = 137) was significantly higher than in those with no history of infertility (n = 140) (22.6% vs 8.6%; p = .001). The prevalence of CE between women with primary infertility and those with secondary infertility was similar (25.0% vs 19.3%; p = .43). Clinical pregnancy (32.3% vs 41.5%; p = .35), live birth (29.0% vs 38.7%; p = .33), and miscarriage (10.0% vs 6.8%; p = .73) rates were similar between infertile women with treated CE and those without CE. A multivariate model showed that diagnosis of infertility was significantly associated with the diagnosis of CE (odds ratio, 3.16; 95% confidence interval, 1.53–6.49).ConclusionIn women with endometrial polyps, the prevalence of CE in infertile women is higher than that in fertile women. Pregnancy outcome in infertile women with treated CE was similar to those who were infertile and without CE.