Objective <p>To determine the incidence and identify independent risk factors of central venous catheter (CVC)-related thrombosis in critically ill children admitted to a pediatric intensive care unit in a middle-income country, and to contribute context-specific prospective data relevant to clinical practice.</p> Methods <p>In this prospective observational study, catheterization episodes in children undergoing central venous catheter (CVC) placement were systematically screened with Doppler ultrasonography within 24–48h after insertion and weekly thereafter. Clinical and catheter-related variables were analyzed using multivariable generalized estimating equation models with a logit link to identify independent predictors of catheter-associated thrombosis.</p> Results <p>A total of 129 catheters, including 105 infusion catheters and 24 hemodialysis catheters, corresponding to 111 catheterization episodes were evaluated in 103 children. Thrombotic events related to CVCs occurred in 22 of 111 catheterization episodes (19.8%). In the overall cohort, multivariate generalized estimating equation analysis identified a history of thrombosis as an independent predictor of CVC-related thrombosis. In the infusion catheter subgroup, femoral vein CVC placement and catheter dwell time &gt; 7&#xa0;days were additional independent risk factors.</p> Conclusions <p>Approximately one in five catheterization episodes in critically ill children was associated with thrombosis. History of thrombosis was an independent predictor overall; femoral vein CVC placement and CVC dwell time &gt; 7&#xa0;days were significant in the infusion catheter subgroup. These findings emphasize the need for risk-adapted ultrasound surveillance and careful catheter management in high-acuity, resource-limited pediatric intensive care settings.</p>