A case-control study was conducted in Singapore, in order to examine a proposed association between schizophrenia and the HLA DQB1 gene locus. The probands were male inpatients of Chinese ethnicity with schizophrenia (ICD-10 criteria, n = 102) and the controls were adults matched for gender and ethnicity (n = 111). Polymorphisms of the HLA DQB1 gene were examined using molecular typing by reverse dot-blotting (MTRB), a novel PCR based method. Among the patients, a positive association with HLA DQB1*0303 (odds ratio 4.46, C.I. 1.63, 12.17), as well as a negative association with HLA DQB1*0602 (odds ratio 0.22, C.I. 0.18, 0.83) was detected.