In a case-control study of 169 preeclamptics and 201 controls, we assessed maternal parental history of chronic hypertension and diabetes in relation to preeclampsia risk among Peruvian women. Participants provided information on parental history of the two conditions and other covariates during postpartum interviews. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for confounding by age, parity and prepregnancy adiposity. In this population, women were more likely to know the diabetes status of their parents than their hypertension status. Compared with women without a parental history of hypertension, women with a parental history of hypertension experienced a 20% increased risk of preeclampsia (OR = 1.2; 95% CI 0.7-2.2) that did not reach statistical significance. Women with a positive parental history for diabetes had a 3.4-fold increased risk of preeclampsia (95% CI 1.4-8.4). Women with a positive parental history of both hypertension and diabetes, as compared with those whose parents had neither condition, experienced a 4.6-fold increased risk of preeclampsia (OR = 4.6; 95% CI 0.9-23.0). Our results are generally consistent with the thesis that parental history of hypertension and diabetes reflects genetic and behavioral factors whereby women may be predisposed to an increased risk of preeclampsia. Copyright © 2003 S. Karger AG, Basel.