An 8-mm diameter rigid lens telescope with a focal distance of 20 cm was developed for open microsurgery. The telescope was attached to a 3-chip high-definition digital camera and then to a high-definition monitor. A pneumatic scope holder permitted repositioning. The optical quality of the device was compared with the operating microscope with a step wedge and 1-mm grid paper. Craniotomies and microsurgical dissections with the telescope system (high-definition exoscope system) were performed in a live pig model. The high-definition exoscope system provided image quality that rivaled the operating microscope even at high magnification. The system was easy to manipulate and comfortable during neurosurgical operations. The lack of stereopsis was a relative drawback of the system but was compensated for with repeated procedures. Overall, this prototype telescope-based system rivals the operating microscope optical quality and field of view. With further refinement, this system could have widespread application in many microsurgical disciplines.