BACKGROUND: Robotic assistance in microsurgery could enhance human precision and dexterity to improve clinical outcomes. Because no robotic device has been designed primarily for microsurgery, the authors developed a dedicated microsurgical robotic system. This preclinical study investigates whether microsurgical anastomosis can be successfully completed on silicone vessels using a prototype of this new robotic system, and compares outcomes of robot-assisted versus conventional microsurgery. METHODS: Three participants at different levels of microsurgical training completed 10 anastomoses by hand and 10 anastomoses with robotic assistance. Four blinded, experienced microsurgeons evaluated the quality of the microsurgical skills using a modified version of the Structured Assessment of Microsurgical Skills. Time to perform the anastomosis and adverse events were recorded. RESULTS: The total time to perform the anastomoses with and without robotic assistance decreased to 35.1 minutes and 12.5 minutes, respectively, during the study. The overall performance and indicative skill of the Structured Assessment of Microsurgical Skills improved with the conventional method (from 2.8 to 3.6 and from 2.6 to 3.7, respectively) and the robot-assisted method (from 2.3 to 3.0 and from 2.3 to 3.1, respectively). CONCLUSIONS: It is feasible to complete anastomotic microsurgery on silicone vessels using the MicroSure robotic system. In comparison with the conventional method, time to perform the anastomosis was longer and quality of microsurgical skills was lower in the robot-assisted group. However, the robot-assisted performance showed steeper learning curves for both surgical time and domains of microsurgical skills. The encouraging results indicate further development of the system and (pre)clinical trials.