Infections are still a major cause of morbidity and mortality in end-stage renal disease (ESRD) patients. The susceptibility of ESRD patients to infections is typically ascribed to the immunodeficient state associated with uremia. A central role in the host defense against bacterial infections is played by phagocytic polymorphonuclear white blood cells, which are characterized by the capacity to ingest and subsequently destroy bacteria. Disorders in polymorphonuclear cell function are exacerbated by the dialysis procedure and numerous factors including uremic toxins, iron overload, anemia of renal disease, and dialyzer bioincompatibility. It is concluded that the phagocytic defect observed in ESRD is multifactorial, and each factor should be managed individually with specific therapeutic approaches.