This article presents a novel approach to the modeling and reduction of electromagnetic interference (EMI) caused by radiated emissions of integrated circuits (ICs) inside rectangular metallic enclosures of telecommunications devices. This type of analysis applies for several types of modern telecommunications equipment found in highspeed networks as well as in mobile communications. A generic model of such a device is created. The ICs are modeled as small electric dipoles and their interaction with the enclosure walls is studied by using the dyadic Green's functions. The electric field on the enclosure walls is computed and its reduction is studied as optimization problem using evolutionary algorithms. Two algorithms are employed: Genetic algorithms (GAs) and parallel recombinative simulated annealing (PRSA). PRSA is a hybrid evolutionary strategy that inherits properties from both GAs and simulated annealing. Monte Carlo simulation is subsequently applied to the optimization results to derive the electric field on the metallic walls and also to perform a worst-case analysis. The applications of the above approach in early PCB design process are discussed.