Abstract Takayasu's arteritis (TA) and tuberculosis (TB) have been associated with major histocompatibility complex genes, especially HLA‐B alleles. However, different HLA‐B alleles have been detected in these diseases. The aim of the study was to compare the distribution of the residues 63 and 67 on the HLA‐B molecule in patients with TA and TB in order to establish a genetic relationship between these two diseases. HLA‐B sequences obtained in 30 patients with TB were compared to those previously reported in TA and healthy controls. 8 out of 30 TB patients studied (26.6%) presented at least one allele with glutamic acid at position 63 and serine at position 67. This was observed in 73% of the TA patients ( p = 0.0005). Ten TB (10/30 = 33.3%) and two TA patients (2/26 = 7.7%) did not show similarity at the mentioned positions ( p = 0.019). This preliminary study suggests a difference in the distribution of the residues 63 and 67 of the HLA‐B alleles in patients with TA and TB. Copyright © 2008 John Wiley & Sons, Ltd.