Three studies have reported a negative genetic association between schizophrenia and HLA DQB1*0602, an allele of the human leucocyte antigen (HLA) DQB1*06 gene. In a sample of ethnic all homogeneous Caucasians living in Sweden, the frequency of HLA DQB1 alleles in patients with schizophrenia (n = 124) was compared with that in a control group (n = 85). No significant differences were found. Together with previous investigations, the present study indicates that the reported genetic association of DQB1*0602 with schizophrenia may be limited to non-Caucasians.