It has been reported that aplastic anemia (AA) is more common in HLA-DR2-positive individuals than in the general population. We investigated the frequency of some HLA loci of 102 Northern Han Chinese patients with AA and 105 healthy control subjects. Polymerase chain reaction and sequence specific oligonucleotide probe hybridization were used to determine HLA-DR- and HLA-DR2-related DRB1 alleles. The frequency of DR2 is increased in AA patients; the relative risk (RR) was 2.86, and the difference was significant (chi 2 = 11.1, P = .004). The RR of HLA-DRB1*1501 was 3.07, and the difference was significant (chi 2 = 9.42, P = .008). The above results suggest that HLA-DR2 is significantly associated with AA in Northern Han Chinese. HLA-DRB1*1501 is the main subtype of HLA-DR2, and may be the susceptibility gene of AA.