Abstract. This paper presents a worst-case performance analysis for Lur'e systems with time-invariant delays. The sufficient condition to guarantee an upper bound of the worst-case performance is developed based on a delay-partitioning Lyapunov-Krasovskii functional containing an integral of sector-bounded nonlinearities. Using Jensen inequality and -procedure, the delay-dependent criterion is given in terms of linear matrix inequalities. In addition, we extend the method to compute an upper bound of the worst-case performance of Lur'e systems subject to norm-bounded uncertainties by using a matrix eliminating lemma. Numerical results show that our criterion provide the least upper bound on the worst-case performance comparing to the criteria derived based on existing techniques.