Abstract: An underfloor cable trough assembly can be employed in new or existing raised floor assemblies having removable floor panels supported at a preselected height above a subfloor by a series of vertical pedestals. Modular cable trough sections are disposed between the subfloor and the raised floor panels and can be joined to form a trough network. At least some of the trough sections have apertures formed in their side walls at regularly spaced intervals. Removable cover plates are disposed in the side wall apertures. The cover plates serve as a portion of the trough side wall when installed and are removable to permit individual trough sections to be joined to each other. In addition, the removable floor panels serve as covers for the trough sections.