Abstract: A modular screening system which includes a plurality of screening modules supported in an interlocking manner of clamping bars secured to and positioned across a screening machine in parallel spaced relationship. The modules have a peripheral portion defined by side and end walls with a plurality of openings extending through the modules inwardly of the peripheral portion. The side and end walls of the modules are provided with interengaging means which interlock with longitudinal and transverse channels in the clamping bars to secure the modules in position in the machine, the modules are provided with interengaging means whereby the modules interlock together.