Abstract: Histopathologic study of skin lesions were carried out in 72 cases of borderline leprosy,including BT 25 cases,BB 25 cases; and BL 22 cases.The most significant cells in the formation of the lesion found between two polar types of leprosy were atypical foamy cells which onsist of epitholioid foamy cells.and fibrocyte-like foamy cells,these atypical foamy cells contributed to the features of borderline lesion.Lesions of BT were mainly formed by vacuolated epithelioid cells,associated with more lymphocytic infiltration at the periphery of the lesions.Leprosy bacilli were found in small amount.Lesions of BB were mainly formed equally by epithelioid cells and atypical foamy cells,sometimes with predominance of the latter.The lymphocytic infiltration as well as leprosy bacilli were moderate in amount.The cells found.in BL lesions were mainly atypical foamy cells.Sometimes the predominant cells were epithelioid foamy cells,and at times fibrocyte-like foamy cells were predominanto The lymphocytes were few in numberwith scattered distribution,while infiltration of plasma cells were found in a few cases.Leprosy bacilli were found in large amount in most cases.The morphology of regression in borderline leprosy is similar to that of tuberculoid leprosy.