To compare of result according to fracture comminution and fracture site, we reviewed retrospectively 68 femoral shaft fractures treated by closed interlocking intramedullary nailing. The Winquist-Hansen classification was used to categorize the degree of comminution, and fracture site was categorized to three parts as proximal 1/3, middle 1/3, and distal 1/3. The results were analized and compared in each categorized group The average bone union time was delayed in more severely comminuted fracture and in distal 1/3 fracture compared to proximal 1/3 or middle 1/3. Varus angulation deformity was occurred more frequently in proximal 1/3 and severely comminuted fracture group, and posterior angulation deformity was occured more frequently in distal 1/3 fracture group. All but one case showed good functional results regardless of fracture comminution, fracture site and development of malalignment.