Arterial access for blood sampling and continuous blood pressure monitoring is the cornerstone of modern neonatal intensive care. Although umbilical arterial catheters have traditionally been utilized for arterial access, they are associated with potentially devastating complications. Consequently, there has been an increase in the use of peripheral arterial catheters. Unfortunately, these catheters have a limited useful lifespan secondary to vasospasm, intimal damage and/or thrombus formation. In this report, we describe the use of tolazoline (0.02 to 0.2 mg/kg/h) to counteract local arterial vasospasm in five critically ill neonates, where arterial access was vital for care but difficult to maintain.