Central venous access devices are extensively used for long-term chemotherapy and parenteral nutrition. However, there are some possible immediate, early, and late complications related to the implantation technique, care, and maintenance. We present the uncommon occurrence of a thrombosis of the internal jugular vein due to a spontaneous migration of a Port-A-Cath catheter into the ipsilateral internal jugular vein as a delayed complication of a central venous access catheter implanted for chemotherapy delivery. A review of the literature is given, and the factors responsible for this unusual complication will be discussed.