Central venous catheter (CVC) placement is associated with increased risk of thrombosis in the paediatric population, particularly in relation to the type of catheter and the manner of its insertion. Here, we investigate risk factors associated with CVC-related thrombosis in children, with particular emphasis on positioning of the catheter tip. Patients aged 0-18 who underwent at least one CVC placement from 2008 to 2013 at a single centre with a subsequent follow-up echocardiogram were included for a total of 104 patients and 147 lines. Data on clinical and catheter-related risk factors were collected from patient charts. Statistical analysis using Pearson's χ tests, independent samples t-test, and odds ratios were used to assess potential risk factors for thrombosis. Neither insertion site (subclavian vein or otherwise), left- vs. right-sided insertion, nor catheter type were significant risk factors for thrombosis. There were no thrombotic events reported at the superior vena cava (SVC)-right atrium junction and no significant differences in thrombotic risk with initial tip placement in the SVC-right atrium junction vs. the SVC, right atrium, or inferior vena cava. Acute lymphoblastic leukaemia was a major clinical risk factor for thrombosis. Tip movement was common and may have been an important factor in the development of CVC-related thrombi. Prospective studies can yield insight into the role of follow-up imaging in the prevention of catheter-related thrombosis in children.