The use of extracorporeal techniques for the treatment of pediatric diseases has expanded dramatically in the past decade. During this time, experience with both plasmapheresis and renal replacement therapy has become commonplace in ICUs and nephrology programs throughout the world. The indications for these therapies range through treatment of vasculitis, drug removal, support from inborn error metabolism, multiorgan system failure, primary renal disease, and sepsis. Because these therapies are somewhat intermingled based on the commonality of the need for vascular access, extracorporeal blood volumes, and bedside nursing support, and furthermore because the indications for these may overlap, these therapies are often used in tandem or parallel to support the child with illness.