Endometrial polyps can be difficult to diagnose, especially when they are encountered in specimens obtained by biopsy or curettage. We evaluated 71 cases of grossly identifiable polyps from hysterectomy or polypectomy specimens for various histologic features and correlated the frequency of these features with variables such as menstrual state, histopathologic type, and shape of the polyps in order to find out diagnostic parameters in biopsy or curretage specimens. The most frequently observed histologic findings in both premenopausal and postmenopausal women were the presence of thick walled vessels and irregularly shaped glands (91.5% and 97.2%, respectively). In addition, we evaluated another histologic feature, the parallel arrangement of the long axes of endometrial glands to the surface epithelium in 33 of 71 (46.4%) endometrial polyps. It was more common in polyps excised from premenopausal (56.4%) than in postmenopausal women (34.3%) and was found in 7 of 8 (87.5%) functional polyps, while 40.6% of hyperplastic polyps showed this feature. The presence of thick walled vessels is the most frequently identified histologic feature in endometrial polyps. Parallel arrangement, when present, could be an additional clue in the diagnosis of endometrial polyp in routine curettage specimens.