Abstract: The adaptive synchronization is discussed for a class of delayed Ikeda chaotic systems, where the construction and part of parameters of drive and response systems are different with the rest of parameters unknown. Based on Lyapunov stability theory and Barbalat lemma, an adaptive synchronization controller is designed with the adaptive law of parameters given. The designed controller is easy to implement in practice to enable two different delayed Ikeda chaotic systems to synchronize asymptotically with each other. The proposed method is applicable to not only the delayed Ikeda chaotic systems but also the bounded and continuously delayed chaotic systems in any state. Simulation results verified the effectiveness of the method.