The endometrium of 25 Holstein-Friesian cows, collected at 40-45 days postpartum, were examined to determine the state of histologic involution of the uterus. Changes in the uterine glands and the presence of cellular infiltrate and periglandular fibrosis were valuated histopathologically. Most cows had lymphoid nodules (88%) and slight periglandular fibrosis (80%). The cellular infiltrate were predominantly lymphocytes. The degree of inflammatory reaction in the endometrium was slight in 6 cows (24%), moderate in 13 cows (52%) and severe in 6 cows (24%). None had a normal endometrium. Significant differences were observed in the endometrial inflammatory cell counts between cows with normal and abnormal puerperium, and in the mononuclear cell infiltration between cows with normal and delayed uterine involution. Results indicated the absence of normal endometrium at 40-45 days postpartum and the association of endometrial inflammation with postpartum problems.