Human interferon-gamma receptor 1 (IFNGR-1) deficiency is a newly identified autosomal recessive inherited immune disorder. Children with IFNGR-1 deficiency exhibit a severe, profound and selective susceptibility to weakly virulent mycobacteria, such as bacillus Calmette-Guerin (BCG) vaccine or environmental nontuberculous mycobacteria (NTM). This review compares the infections found in IFNGR-1-deficient children to those in IFN-gamma-deficient or IFNGR-1-deficient mice.