This article presents the results of the application of a quite simple method for analyzing shell-side fouling in shell-and-tube exchangers, capable of taking into account the formation of irregular fouling deposits with variable thermal conductivity. This method based on the utilization of elementary hear exchangers, has been implemented for E-shell TEMA-type heat exchangers with two tube passes. Several fouling deposit distributions have been simulated so as to ascertain their effects on the heat transfer rate. These distributions consider that fouling is concentrated in zones where the temperature of the fluids is maximum or minimum.