Objective: To evaluate the capacity of red cell distribution width (RDW) to predict mortality in children undergoing cardiovascular surgery at the Fundación Hospital Infantil Napoleón Franco Pareja, in Colombia.Method: Retrospective cross-sectional analytical study that included 45 individuals aged 0 to 17 years operated for congenital heart disease.The RACHS-1 (Risk Adjustment in Congenital Heart Surgery) scale and laboratory variables including the RDW were applied.The association between RDW and mortality was determined by ROC curve analysis and Spearman's rho correlation.Results: An RDW greater than 15.52% represented 1.6 times more risk, compared to individuals below that value (95% confidence interval: 1.01-2.6;p = 0.034).The RDW values did not correlate with days of hospital stay or complications.The preoperative RDW and RACHS-1 score were significantly higher in the mortality group.The relationship between presurgical RDW and the RACHS-1 score was significant.Conclusions: In our study, the preoperative RDW had moderate power to discriminate perioperative mortality in the surgical correction of congenital heart disease.More studies with a larger sample size are required.