Objective To explore the association of human leukocyte antigen (HLA) with pregnancy induced hypertension (PIH).Methods We oligotyped HLA-DQA1, -DQB1 locus of 30 Chinese PIH families and 14 control families in Shanghai area by polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) hybridization method (probes labeled by nonradioactive technique).Results Compared with the control group, the allelic frequency of HLA-DQB1*0502 was significantly higher in PIH couples, and the sharing of HLA-DQA1 increased in PIH couples as well. No difference was found in HLA-DQA1 allelic frequencies or HLA-DQB1 sharing between the two groups. Analysis of neither HLA-DQA1 nor HLA-DQB1 allelic frequencies in PIH patients and PIH mother-and-fetuses showed positive result.Conclusion HLA-DQB1*0502 may be a marker of susceptibility to PIH. DQB1*0502 itself or some gene(s) located in HLA class Ⅱ region and in linkage disequilibrium with 0502 affect matal T cell immunity during pregnancy. The increase of compatibility in HLA-D region causes the production of blocking antibody to decrease.