Insulin resistance appears to be a causative mechanism for the development of essential hypertension. Insulin resistance syndrome consists of a cluster of abnormalities that aggravate preexisting tendencies to develop hypertension, resulting in a cascade of physiologic alterations and ultimately leading to increased rates of heart attack, stroke, and peripheral vascular disease. Like hypertension, NIDD is mediated by insulin resistance and is expressed in individuals with limited beta-cell reserve. Episodes of increased insulin resistance, such as aging, weight gain, and pregnancy, cannot be compensated for in these states, and glucose intolerance results. In the case of pregnancy, the temporary state of insulin resistance unmasks individuals with an early beta-cell defect and allows for identification of high-risk groups at a time when therapeutic interventions could result in primary prevention of disease. Evidence is beginning to accumulate that preeclampsia is at least partially mediated by insulin resistance as well, and that individuals with preeclampsia may have clinically silent but persistent alterations in insulin resistance. If this condition proves a corollary to gestational diabetes, there may be an opportunity to intervene for primary prevention of some forms of essential hypertension as well. The availability of new pharmacologic agents to enhance insulin sensitivity represents a true opportunity effectively to prevent the long-term complications associated with insulin resistance and hyperinsulinemia. To achieve this goal, early and accurate identification of populations at risk is essential. A complete understanding of the role of insulin resistance in the generation of preeclampsia will aid significantly in the discovery of the genetic polymorphisms and intracellular pathways by which insulin resistance is translated into cardiovascular disease, stroke, and nephropathy.