The central nervous system plays an important role in the minute-to-minute regulation of arterial pressure, but its contribution to chronic regulation of arterial pressure is less clear. A nervous system role in essential hypertension in humans has been postulated for decades, but conclusive data on the relationship has been lacking. However, several lines of evidence in animal models and in humans suggest that the sympathetic nervous system is a primary contributor to the development and maintenance of some forms of essential hypertension. The primary final common pathway for the nervous system's contribution to hypertension is the sympathetic nervous system. Sympathetic nervous system overactivity may result from either inappropriately elevated sympathetic drive from brain centers, an increase in synaptically released neurotransmitters in the periphery, or amplification of the neurotransmitter signal at the target tissue. This review examines recent evidence for the central and peripheral nervous systems' roles in hypertension, and considers recent findings in this area that suggest that sex steroids and circadian rhythms are important considerations in the nervous system's regulation of arterial pressure. Copyright © 2001 by Current Science Inc.