Chronic plasmacytic endometritis (CPE) is an infectious or reactive process with multiple etiologies. The lesion is reportedly often associated with pelvic inflammatory disease and intermenstrual bleeding. However, the clinical significance of the diagnosis when found incidentally and whether particular pathologic findings are associated with clinically important CPE have not been evaluated. We reviewed 105 chronic endometritis cases that had been diagnosed earlier and 130 controls to examine the pathologic and clinical associations in a diverse population.A pathology database was searched for endometrial biopsies diagnosed as CPE, and 105 cases were found. Systematic randomized sampling identified 130 control cases (biopsies not diagnosed as CPE). Slides were carefully reviewed to assess 10 histopathologic features. Clinical records were reviewed for 15 clinical parameters. Analysis was performed using chi tests and SAS software.Few patients (3%) received antibiotics or further clinical intervention after the diagnosis of CPE was rendered. The clinical data trended toward fewer menstrual abnormalities as plasma cells increased. The intensity of inflammation showed no association with patient age or symptom duration. Evaluation of controls revealed 17 cases with missed diagnosis of CPE, representing an overall 16% underdiagnosis rate.In CPE, there are no specific clinical features that correlate with the intensity of pathologic findings; the most specific histologic feature is the presence of plasma cells, and it is predominantly identified in weakly proliferative endometrium. There is a clinically insignificant 16% pathologic underdiagnosis rate. In contrast to the findings of past studies, only a small percentage of patients had pelvic inflammatory disease (4%).