The use of percutaneous central venous catheters in neonatal intensive care units is becoming increasingly common. Numerous studies support the safety and effectiveness of the use of these catheters for the infusion of parenteral nutrition or medication. We describe a male patient with a gestational age of 32 weeks who showed swelling of the external genitals during the fifth day of life. The etiology was initially thought to be infectious. A review of X-rays revealed the introduction of the silastic catheter to the spermatic vessels. When the catheter was withdrawn, the genital swelling disappeared in a few hours. The most frequently described complications associated with percutaneous central venous catheters are infectious. Other complications that have been described are thrombosis, embolism, and perforation of the catheter with leakage of fluid to the extravascular space. The case described herein is an unusual complication that has not been previously described and resulted from poor positioning of the catheter tip. Diagnostic delay can cause serious complications.