Background: Central venous catheter (CVC) cannulations are associated with complications like arterial puncture, hematoma, pneumothorax and arrhythmias. These complications may be particularly dangerous in paediatric patients. Aim of the work: This was a prospective 6 month study to assess the incidence of mechanical complications to central venous catheters at the pediatric intensive care unit (PICU) of Ain-Shams University Hospital. Patients and Methods: present study was a prospective observational study conducted on 109 patients with a 152 CVCs inserted to them who were admitted to the Pediatric Intensive Care Unit of Ain Shams University Hospital from July to December 2017. They were observed for development of mechanical complications including arterial puncture, failed insertion, bleeding, false passage, pneumothorax, arrhythmia. Results: Among the total studied of 152 CVC cannulations, mechanical complications occurred in 6.6 % of cases. The complications included failed insertion (1.3%), arterial puncture (0.7%), false passage (0.7%), bleeding with hematoma (1.3 %), arrhythmia (1.3 %) and pneumothorax (1.3 %). Conclusion: mechanical complications have a low incidence in our study due to the use of ultrasound guidance during CVC insertion.