Objective: Methods in restorative dentistry have to meet stringent accuracy requirements. The accuracy of robotic systems used for the reproduction of condylar movements has not been determined. The purpose of this study was to assess the accuracy of the robot system, ROSY, a robotlike electronic simulator (developed by the author) that reproduces condylar movements previously recorded on a patient. Method and materials: The simulator consists of a custom-designed ultrasonic system that records mandibular movements in all three dimensions (vertical, horizontal, and coronal) with six degrees of freedom. The simulator automatically reproduces all movements around these axes with a robotic system with six stepper motors. The accuracy of the simulator was measured for all directions in space by registering eccentric jaw positions on both sides of 10 subjects in two ways: (1) by the ultrasound registration system; and (2) simultaneously with an interocclusal recording medium.The standard deviation and interquartile range of the differences between the measurements based on these two approaches were used to statistically describe the accuracy of ROSY. Results: The accuracy of the entire system was better than 0.28 mm. Conclusion: The electronic simulator comes with an accuracy that may render it suitable for clinical applications.