Intramedullary nailing for a fractured tibia has been used in cases of fresh diaphyseal fractures. Recently the usage has been expanded considerably with modern technical improvements. The purpose of this study is to evaluate the results and the complications of interlocking nailing. We reviewed 18 distal tibial shaft fractures that were treated with unreamed interlocking intramedullary nails at the Department of Orthopaedic Surgery, Chosun University Hospital from March 1989 to December 1991. The follow up period ranged from 12 to 24 months. The results were as follows. 1. We used an unreamed interlocking intramedullary nail which was one millimeter smaller than the diameter of the isthmic portion with the dynamic screws in 2 cases and static interlocking screws in 16 cases. 2. The average time of radiologic union was obtained in 17.7 weeks in unreamed interlocking intramedullary nailing. 3. According to the criteria of functional results by Klemm and Borner, excellent and good results are 94.4% (17 out of 18 cases). 4. In the treatment of unstable fractures such as long oblique, spiral and comminuted fractures, we think that unreamed interlocking intramedullary nailing is optimal due to its technical simplicity and stability.