Kinematic calibration is the process of determination of actual robot parameters using the nominal geometric parameters of the robot and specific measurements made on the robot. For a new robot, kinematic calibration is essential for improving the end point accuracy. The RoboTwin is a modular, expandable and re-configurable robot system, designed and patented by Robotics and Automation Lab (RAL), University of Toronto. It can be configured in one of many configurations. Kinematic calibration of such a system possesses a new challenge as the calibration methodology has to be generic enough to be configuration independent. This thesis presents a calibration methodology for a re-configurable robot system (RoboTwin). The calibration methodology developed is implemented on the RoboTwin. A user interface is developed to guide the user through the task of calibration. The results of calibration for two RoboTwin configurations are presented. (Abstract shortened by UMI.)