Objectives. - Despite its simple definition, preeclampsia can have variable and atypical clinical presentations, an unpredictable course, and potential adverse maternal and fetal outcomes. No single test currently predicts risk or prognosis adequately. Scientific advances suggest that an angiogenic imbalance is involved in its pathophysiology. The objective of this study was to investigate the use of sFlt-1, PlGF, and their ratio in predicting preeclampsia. Materials and methods. - In a single-center prospective observational study, we measured the angiogenic markers sFlt-1 and PlGF and calculated the sFlt-1/PlGF ratio in patients at risk of preeclampsia at 20 to 37 weeks of gestation. The main outcomes were the occurrence of preeclampsia and the interval before its onset. Results. - Of the 67 at risk patients included, 8 (12%) developed preeclampsia. For a sFlt-1/PlGF ratio >= 85, the specificity was 93%. The ratio was significantly higher (ratio = 104 30) in women with an onset time less than 5 weeks than in those with later preeclampsia (ratio = 10 2), P < 0.001. Conclusion. - In a high-risk population, angiogenic markers appear to be an interesting aid in predicting the onset of preeclampsia with high specificity and in estimating time to onset. However, due to small number of cases of PE, more studies are needed before recommendations to use these markers in daily practice.