Preeclampsia is a pregnancy specific disorder characterised by hypertension and proteinuria occurring after the twentieth week of gestation. Preeclampsia induced hypertension is the result of increased vascular reactivity and endothelial dysfunction, however, the mechanisms underlying this state remain elusive. One possible mediator may be the matrix metalloproteinases (MMPs), a family of proteinases typically recognized for long term tissue remodelling. This review examines the evidence suggesting a role for MMPs in acutely regulating vascular function. Studies have shown that MMPs can activate vasoconstrictors (e.g. endothelin), inactivate vasodilators (e.g. calcitonin gene related peptide) and transactivate cell surface receptors responsible for vasoconstriction (e.g. epidermal growth factor receptor). The potential role of these proteinases in preeclampsia will then be discussed.