Design-oriented stability criteria are developed for ac power systems with regulated electronic loads. The systems are assumed to contain rotating machines as well as regulated solid-state switching power converters. The system models are developed such that the generalized Nyquist and Bode techniques are possible. Then small-disturbance stability criteria are set forth. The stability constraints are simplified and formulated in terms of different subsystem matrix input impedance norms. An example system is analyzed using the proposed techniques. A comparison with time domain simulations and eigenvalue analysis is performed to validate the advanced stability criteria.