The objective of this study was to analyze hematologic disorders, coagulation disorders, and transfusion requirements in children with continuous renal replacement therapies (CRRT). This is a retrospective analysis of a prospectively collected database of children receiving CRRT between 2010 and 2015. Patient characteristics, CRRT parameters, hematologic and coagulation parameters, and need for transfusions were recorded and analyzed. We compared patients after heart surgery and noncardiac patients, those requiring extracorporeal membrane oxygenation (ECMO) and those without ECMO, and patients with different anticoagulation therapies: heparin and citrate. Eighty-seven patients were included (69% after heart surgery). Thirty-four percentage of patients required ECMO. Hematologic alterations throughout the therapy included a descent in hematocrit from 33.6% to 30.3% (p = 0.002) and in platelet count from 159.291 to 101.163 (p < 0.001). Coagulation parameters improved as international normalized ratio decreased from 1.5 to 1.2 (p < 0.001), fibrinogen increased from 328 to 437 mg/dl (p = 0.04), and activated partial thromboplastin time (APTT) was normalized. There were no significant differences in hematologic parameters or need for blood products between patients after heart surgery and the rest of patients, or between patients receiving heparin or citrate for anticoagulation. Ninety percentage of patients received blood products, but patients on ECMO and those who deceased required more transfusions than the rest of the patients (p < 0.01). We conclude that children undergoing CRRT show a descent in hematocrit and platelet count and require large amounts of blood products, especially those ECMO and patients who died.