Radial artery pseudoaneurysm is a rare complication of radial artery cannulation, with underlying infection rarer still. A pseudoaneurysm is formed when there is exsanguination, secondary to penetrating injury between the two outer layers of an artery: the muscularis propria and the adventitia. We report a case of radial artery pseudoaneurysm infected with pseudomonas aeruginosa in a 73-year-old male who had radial artery cannulation for perioperative monitoring during coronary artery bypass grafting.