This paper provides a new delay-dependent stability criterion for systems with a delay varying in an interval. With a different Lyapunov functional defined, a tight upper bound of its derivative is given. The resulting criterion has advantages over some previous ones in that it involves fewer matrix variables but has less conservatism, which is established theoretically. Examples are provided to demonstrate the advantage of the stability result. (C) 2008 Elsevier Ltd. All rights reserved.