Central venous catheters (CVC) are now commonly inserted by radiologists. Although complications are infrequent, they must be avoided where possible and recognized when they occur. We present a 10-year-old boy who developed right hemidiaphragmatic paralysis, requiring surgical plication, following US-guided insertion of a tunnelled right internal jugular CVC. The needle trajectory for internal jugular puncture must be planned to avoid the phrenic nerve.