Pre-eclampsia is a common, pregnancy-induced disorder, consisting of hypertension and proteinuria. The condition is one of the leading causes for maternal and perinatal morbidity and mortality. Nonetheless, the underlying molecular mechanisms remain unclear. Immunological mechanisms and the renin-angiotensin system have been implicated in the development of pre-eclampsia. Agonistic autoantibodies to the angiotensin II type I receptor (AT1-AA) have been identified in pre-eclamptic patients, unifying the two hypothesis. Evidence has also accumulated for the existence and importance of a local, utroplacental renin-angiotensin system. We summarize recent data emphasizing the pathophysiological role for the autoantibodies and the uteroplacental renin-angiotensin system.