Background. Primary thrombotic microangiopathy includes hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli, atypical hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura. Methodology. A retrospective study that included patients younger than 18 years diagnosed with primary thrombotic microangiopathy between 2011 and 2021. Results. Thirty patients were included, of which 63% corresponded to a hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli, and 30% to the atypical hemolytic uremic syndrome. The median age was 2.8 years and female sex predominated at 57%. On admission to the emergency room, fever and fatigue were the most frequent symptoms (93%), followed by oliguria and anuria (80%). 48% of patients received hemodialysis during their care. Mortality was estimated at 13%. Conclusion. This study constitutes the largest series of primary thrombotic microangiopathy in the pediatric population of Latin America, where the etiological and clinical behavior of this condition is described.