The purpose of this study was to evaluate the clinical accuracy of femoral canal preparation using postoperative reconstructed computed tomography (CT) images of 75 consecutive total hip arthroplasties performed with a two-pin-based ROBODOC system. Intraoperatively, the robot milled the femoral canal according to the preoperative planning performed with preoperative CT data and the ROBODOC workstation. Postoperative CT data was obtained 1 month postoperatively. Anteroposterior and lateral synthetic radiographs and axial images were reconstructed from CT data on the workstation. The mean difference between the preoperative planning and the postoperative CT images was less than 5% in canal fill, less than 1 mm in gap, and less than 1 degrees in the mediolateral and anteroposterior alignment. Clinical femoral canal preparation using the ROBODOC system results in a high degree of accuracy.