Interleukin (IL)-8 is involved in the pathogenesis of human tuberculosis (TB). However, the contribution of polymorphisms of the IL-8 gene and its receptor genes CXCR-1 and CXCR-2 to human TB susceptibility remains untested. In a case-control study, white subjects with TB disease were more likely to be homozygous for the IL-8 -251A allele, compared with control subjects (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.52-7.64). African Americans with TB also showed an increased odds of being homozygous for this allele (OR, 3.46; 95% CI, 1.48-8.08). To exclude population artifacts in the case-control study, a separate analysis that used a transmission-disequilibrium test with 76 informative families confirmed that the IL-8 -251A allele was preferentially transmitted to TB-infected children (P=.02). CXCR-1 and CXCR-2 did not demonstrate significant associations with TB susceptibility. These data suggest that IL-8 is important in the genetic control of human TB susceptibility.