The complications associated with central venous access are divided into infectious, vascular, and miscellaneous. Experience with catheterization, ultrasound guidance, and insertion sites are the factors determining rate of complications. Rate of infection due to central venous access depends on insertion technique, use of prophylactic antibiotic or on type of catheter used. Arterial puncture, hematoma, and pneumothorax are the most common mechanical complications during the catheterization of internal jugular vein and subclavian vein. Hematoma and arterial puncture are common during femoral venous catheterization. When accidental cannulation of an arterial vessel occurs, the dilator or catheter should be left in place and a general surgeon should be immediately consulted regarding surgical or nonsurgical catheter removal for adults. Thrombotic complications are high with femoral vein than internal jugular vein and found least with subclavian vein.