A new approach for dynamic reliability and power management of Integrated Systems, such as Systems on Chips (SoCs) and Networks on Chips (NoCs) is presented. With aggressive transistor scaling, decreased voltage margins, and increased processor power and temperature, reliability assessment has become a significant issue in design. Our work combines for the first time dynamic power management with reliability models. The joint model is used to determine system level reliability as a function of failure rates, system configuration and power management policies. We show that the overall system reliability is strongly affected by reliability network topology and power management policy.