Several lines of evidence support an upward revision in pediatric hemodialysis dose guidelines: Although current recommendations are derived largely from studies of dialysis mortality and morbidity in adults, recent reports of improved growth and pubertal development with more intensive dialysis highlight the need for appropriate pediatric outcome measures in the assessment of dialysis adequacy, particularly in prepubertal patients. Even if adult studies can be extrapolated directly to younger patients, reappraisal of these data would appear to justify an increase in recommended dialysis clearances, based on higher dietary protein intake and accumulating evidence that adults, too, benefit from more intensive therapy. Suboptimal dialysis may also occur when dialysis dose is overestimated by urea kinetic models that fail to account for compartment effects and post-treatment urea rebound. Studies comparing the available models in pediatric patients have appeared recently, and a few models have been developed specifically for pediatric applications. These should permit more reliable estimates of solute clearance for a much-needed multicenter trial to clarify optimal dialysis therapy for growing children.