We investigated the impact of preoperative ultrasonography of the forearm circulation on radial artery conduit selection. Preoperative ultrasound of the forearm circulation was performed routinely in 536 patients planned for radial artery harvesting. The safety assessment of the harvest included the following algorithm of tests: the ultrasound, the Allen test, and pulse oximetry. The quality criteria that were used to exclude a radial artery from harvesting were small size of the artery, diffuse atherosclerosis, calcifications, and severe neointimal hyperplasia. The overall rejection rate due to safety reasons was 16.4%. Seventy-one (13.2%) radial arteries did not fulfill the conduit quality criteria and consequently these arteries were not harvested. In 13.4% of radial arteries, localized arterial wall disease was found in the distal third of the artery. The distal part of the artery was discarded and the rest was used as a conduit. Our results indicate that the ultrasound provides an accurate preoperative insight into the radial artery morphology, enabling selection of the arteries with favorable morphological features.