This paper addresses the problems of stability analysis and decentralized control of interconnected linear systems with constant time-delays in the state of each subsystems as well as in the interconnections. We develop delay-dependent methods of stability analysis and decentralized stabilization via linear memoryless state-feedback. The proposed methods are given in terms of linear matrix inequalities. Extensions of the decentralized stabilization result to more complex control problems, such as decentralized static output feedback, decentralized ${\cal H}_{\infty}$ control, decentralized robust stabilization, and decentralized robust ${\cal H}_{\infty}$ control are also discussed.