The paper proposes a formal approach to building software performance models for distributed and/or concurrent software systems from a description of the system’s architecture by using graph transformations. The performance model is based on the Layered Queueing Network (LQN) formalism, an extension of the well-known Queueing Network modelling technique [16, 17, 8]. The transformation from the architectural description of a given system to its LQN model is based on PROGRES, a known visual language and environment for programming with graph rewriting systems [9-11]. The transformation result is an LQN model that can be analysed with existent solvers [5].