Arthroscopic unterior cruciate ligament reconstructions using bone-patelia tendon-bone have been considered the best method by which others are compared. The notchyplasty is one of the important steps of this procedure and it is emphasiz,ed recent]y to prevent retear of the reconstrucled ACL causecl by impingement. However, until now, there is controversy ahout adequate amount of notchyplasty. Also, it is hard to examine the adequacy of notchyp]asty even in the aithroscopic field. The purpose of this paper is to describe the surgical technique of notchyplasty, using the flexible reamer and preliminary result of this procedure. In this study the results of ACL:reconstruction with notchyplasty which is made hy us were analized from January,1994 to December,1995. The results were as follows; 1. The notchyplasty with flexible reamer is the method tbat can be performed adequate amount of removal, and he obtained perfectly smooth notchplasty. 2. The range of motion of the affected knee joint was normal ROM after ppst operation 6 month. 3. In the last follow up, 2 cases were positive in anterior drawer test, 4 cases were positive in Lachmanns tesl., and Case was positive in Pivot shift test. 4. Average Lyshnlm knee scoring scale was 70 points al preoperative and 92 points at the last follow up.