BACKGROUND: At fluid hysteroscopy the presence of endometrial micropolyps (less than 1 mm of size) is a frequent finding. Although their origin is still unknown, in our experience they are associated with stromal edema, endometrial thickening and periglandular hyperhaemia that suggest the existence of chronic endometritis. This study will aim to describe these lesions and evaluate their inflammatory significance by comparing hysteroscopic and histological findings. METHODS: 820 women underwent hysteroscopy and endometrial biopsy. Sensitivity, specificity, positive and negative predictive values and accuracy of the micropolyps presence for the diagnosis of chronic endometritis were calculated. RESULTS: Micropolyps were found in 96 cases (11.7% of all hysteroscopies); in 90 (93.7%) of these cases histology confirmed the presence of chronic endometritis. In women without micropolyps, chronic endometritis was significantly less frequent (78 cases, 10.8%) (P<0.000001). The likelihood of chronic endometritis for women with micropolyps was very high (odds ratio 124.2, confidence interval 50.3–205.4). The sensitivity, specificity, positive and negative predictive values were 54%, 99%, 94% and 89%, respectively; the diagnostic accuracy was 90%. CONCLUSIONS: The presence of endometrial micropolyps at fluid hysteroscopy is significantly associated with endometrial inflammation and can be considered a reliable diagnostic sign for this pathology.