A single-nucleotide polymorphism in the promoter region of the CD14 gene at position 159 has been implicated in susceptibility to infectious diseases. We sought to determine the association between CD14 C-159 T functional promoter polymorphism and brucellosis in Western Iranian population where the disease is endemic. The CD14 genotype was determined in 228 patients with brucellosis from a rural area and 129 healthy volunteers from the same area. The prevalence of genotype TT was significantly higher in the patients while the controls showed higher prevalence of genotype CC (34.5% vs 15.5%, 15.4% vs 25.6%, P = 0.009). Multiple logistic regression analysis after adjustment for gender demonstrated that the patients who were homozygous for allele T of promoter of CD14 gene had a significantly higher risk for developing brucellosis with odds ratio of 3.03 (95% CI, 5.2, 1.75 P = 0.0004). The existence of homozygous genotype of allele T of CD14 was an independent determinant for occurrence of arthritis among the patients with brucellosis (odds ratio of 3.92 (95% CI, 2.93, 5.88, P = 0.001). Our findings provide suggestive evidence of association of the CD14 gene polymorphism with susceptibility to development of brucellosis in Iranian populations.