There is general agreement that a generalized vascular dysfunction, an abnormal interaction between trophoblast and decidua and an exaggerated inflammatory response are involved in the pathogenesis of preeclampsia. We speculate that each of the above described pathogenetic aspects could be elicited or enhanced by an infection occurring before or during pregnancy. Here, we review the existing evidence of an association between infections and preeclampsia and propose hypotheses regarding their role in the development of the disease. Further prospective, well-designed trials are needed to confirm the evidence currently available. The ultimate demonstration of the role of infection in the etiology and pathogenesis of preeclampsia will open up new possibilities for its prevention and treatment.