To investigate the role of inhibitor of kappaBalpha promoter polymorphisms in the pathogenesis of rheumatoid arthritis (RA), 140 patients with RA and 115 healthy controls were enrolled in this study. The IkappaBalpha promoter polymorphisms were determined using the polymerase chain reaction/restriction fragment length polymorphisms method. In comparison with IkappaBalpha-826 C/C, the genotype frequency of IkappaBalpha-826 C/T was significantly higher in the patients with RA than that of the controls (P = 0.009, OR = 2.0, 95% CI = 1.2-3.4). The allele frequency of IkappaBalpha-826 T was also significantly increased in patients with RA when compared with that of the controls (P = 0.027, OR = 1.6, 95% CI = 1.1-2.4). In comparison with IkappaBalpha-550 A/A, the genotype frequency of IkappaBalpha-550 A/T was significantly decreased in patients with RA when compared with that of the controls (P = 0.02, OR = 0.2, 95% CI = 0.06-0.8). The allele frequency of IkappaBalpha-550 A was significantly increased in patients with RA (P = 0.007, OR = 5.1, 95% = 1.4-18.2). This study also revealed that the IkappaBalpha-826 T -550 A -519 C haplotype was significantly increased in patients with RA in comparison to that of controls (P = 0.01, OR = 1.8, 95% CI = 1.1-2.8). The IkappaBalpha-826 T and -550 A alleles are associated with susceptibility to RA. Moreover, the IkappaBalpha-826 T -550 A -519 C haplotype is associated with susceptibility to RA in Taiwan.