The association between human leukocyte antigens (HLA) and the development of preeclampsia (PE) was studied in 48 women with PE and their partners. In 20 of the families, the HLA antigens of the child were also determined. In 8 of 15 cases (53%) of primigravidae with PE, the child shared at least 2 paternal antigens with the mother, whereas this was the case in only 1 of 26 (4%) children of healthy mothers (p < 0.001). In contrast to this, none of 6 children of multigravidae with PE shared 2 paternal antigens with the mother. An increased homozygosity at the HLA-B locus was also seen in the children of primigravidae with PE (40 vs. 4%, p = 0.01).