Insertion of an intravascular catheter is the most common invasive procedure in the neonatal ICU. With every passing decade, technological innovations in catheter materials and sizes have allowed vascular access in infants who are smaller and sicker for purposes of blood pressure monitoring, blood sampling, and infusion of intravenous fluids and medications. There is, however, growing recognition of potential risks to life and limb associated with the use of intravascular catheters. This article reviews complications of venous and arterial catheters in the neonatal ICU and discusses treatment approaches and methods to prevent such complications, based on current evidence.