Background: There is little information regarding complications of arterial catheterization in modern clinical care. We aimed to determine the incidence of abnormal duplex vascular ultrasound and catheter related infections following perioperative arterial catheterization. Methods: Patients requiring arterial catheterization for elective surgery were included and insertion details collected prospectively. Duplex ultrasound evaluation was performed 24 h after catheter removal. Symptomatic patients were identified by self-reported questionnaire. On Day 7, patients answered questions by telephone, related to the insertion site, pain, and function. Results of catheter tip and blood culture analyses were sought. Univariate associations of patient and surgical characteristics with abnormal ultrasound were assessed with p < 0.05 considered significant. Results: Of 339 catheterizations, 105 (40%) had ultrasound evaluation. Catheters were indwelling for median (IQR, range) duration of 6.0 h (4.4–8.2, 1.8–28) with no catheter-related infections. There were 16 (15.2%, 95% CI 9.0%–23.6%) abnormal results, including 14 radial artery thromboses, one radial artery dissection, and one radial vein thrombosis. Those with abnormal ultrasound results were more likely to have had Arrow catheters inserted (68.8% vs 27%, p = 0.023) and more than one skin puncture (37.5% vs 26.8%, p = 0.031). Two of the 16 (12.5%) patients with abnormal ultrasound results reported new symptoms related to the hand compared with nine of the 88 (10.2%) with normal results ( p = 0.1). No patients required urgent referral for management. Conclusions: Thrombosis was the most common abnormality and was usually asymptomatic. There were no infections, few post-operative symptoms, and minimal functional impairment following arterial catheterization.