Objective To investigate the cause and prevention of such sebaceous cysts.Methods Sixty patients undergoing mastopexy or reduction mammaplasty were randomly divided into two groups.Peri-areolar de-epithelialization was performed to a depth of less than one-third of the dermis in group A and nearly the full thickness of the dermis in group B,and the incidence of sebaceous cysts was compared between these two groups.Results Patients were followed-up for 2 to 4 years.In group A,sebaceous cysts at the incision site were found in 4 patients(13.3%);however,no sebaceous cysts occurred in group B.Conclusion Increasing the thickness of de-epithelialization appears to decrease the incidence of sebaceous cysts at the incision site,which would not affect the blood supply to nipple-areola complex.