This work investigated the functional role of nuclear factor–κB (NF-κB) in respiratory burst activity and in expression of the human phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase genes CYBB, CYBA, NCF1, and NCF2. U937 cells with a stably transfected repressor of NF-κB (IκBα-S32A/S36A) demonstrated significantly lower superoxide release and lower CYBB and NCF1 gene expression compared with control U937 cells. We further tested Epstein-Barr virus (EBV)-transformed B cells from patients with anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID), an inherited disorder of NF-κB function. Superoxide release and CYBB gene expression by EDA-ID cells were significantly decreased compared with healthy cells and similar to cells from patients with X-linked chronic granulomatous disease (X91⁰ CGD). NCF1 gene expression in EDA-ID S32I cells was decreased compared with healthy control cells and similar to that in autosomal recessive (A47⁰) CGD cells. Gel shift assays demonstrated loss of recombinant human p50 binding to a NF-κB site 5′ to the CYBB gene in U937 cells treated with NF-κB inhibitors, repressor-transfected U937 cells, and EDA-ID patients' cells. Zymosan phagocytosis was not affected by transfection of U937 cells with the NF-κB repressor. These studies show that NF-κB is necessary for CYBB and NCF1 gene expression and activation of the phagocyte NADPH oxidase in this model system.