Chemiluminescence assay was used to assess the respiratory burst activities of polymorpho-nuclear leukocytes from paediatric patients reported to manifest with several episodes of recurrent bacterial infections. From this group of patients evaluated, only 10 cases of severe recurrent bacterial abscess exhibited more than 80% depression in the phagocytic chemilumi-nescence responses. The assay, being a sensitive method, was able to provide further useful laboratory investigation in diagnosing 4 patients with chronic granulomatous disease.