The polymorphonuclear leukocytes of a two-year-old boy who had multiple episodes of bacterial infections demonstrated defective oxidative metabolism with phagocytic, but not with soluble (non-phagocytic), metabolic stimuli. We used a chemiluminescence assay to examine the patient's polymorphonuclear leukocyte responses to numerous particulate and soluble stimuli. The patient's polymorphonuclear leukocytes had substantially depressed chemiluminescent responses during phagocytosis of opsonized particles (latex, pneumococci, pseudomonas, streptococci and zymosan); however, we observed normal chemiluminescent responses when these leukocytes were stimulated with soluble agents (sodium fluoride, concanavalin A, cytochalasin E, calcium ionophore A23187 or phorbol myristate acetate). Polymorphonuclear leukocyte oxygen consumption and superoxide production were impaired during phagocytosis, even though phagocytosis was normal. In addition to the metabolic defect, this patient's polymorphonuclear leukocytes had depressed chemotactic and bactericidal activities. This study provides evidence that polymorphonuclear leukocytes have more than one mechanism for initiating oxidative metabolism.