The availability of central venous access is the cornerstone of contemporary pediatric oncology and hematology. As a result, the percentage of pediatric patients receiving infusion chemotherapy who require a central line remains high. Central venous catheter insertion can be associated with procedural complications, including life-threatening ones.Aim — to investigate the potential factors leading to complications during central venous catheterization in order to develop preventive strategies.Materials and methods. The study included 1,512 original cases of patients aged 1 month to 20 years treated at the D. Rogachev National Research Medical Center between 2019 and 2022. The following 10 complications were examined: failed first venipuncture attempt, guidewire/catheter malpositioning, guidewire knotting, lifethreatening arrhythmias, guidewire entrapment in the trabecular network of the right ventricle, arterial puncture, pneumothorax, hemothorax, puncture of lung parenchyma, Horner's syndrome. In addition, four rare complications were noted, including phrenic nerve injury, cardiac tamponade, alveolar hemorrhage, and arterial pseudoaneurysm.Results. The primary cause of all complications was direct mechanical injury to anatomical structures by a needle or guidewire/catheter. When inadvertent vascular injury and bleeding occur, the resulting hematoma may lead to further damage by compressing soft tissues. Excessively deep insertion of the guidewire may cause its knotting or cardiac arrhythmias. Adequate physician training and strict adherence to procedural protocols are essential to avoid these complications.Conclusion. Central venous catheterization remains a procedure with potential complications. Although ultrasound guidance does not eliminate all risks, it increases the likelihood of successful venipuncture at the first attempt, thereby reducing complication rates. Recognizing the potential causes of procedural complications during central venous access placement, including uncommon ones, facilitates early diagnosis and appropriate medical intervention.