Abstract: An in-floor access pit unit for use in a floor having a flooring of a predetermined thickness thereon. The access pit basically comprises a rigid liner, a lower frame, an intermediate frame, a cover assembly, and a height adjusting mechanism. The cover assembly comprises an upper frame in which a cover plate is mounted to provide a recess for receipt of a piece of the same flooring material as on the floor in which the access pit is located. The cover assembly is mounted in the intermediate frame by the height adjusting mechanism. That mechanism comprises plural bolts and nuts for adjusting the height of the intermediate frame and the cover member so that the piece of flooring within the cover assembly is flush with the surrounding flooring. The intermediate frame includes a downwardly depending flange which is disposed closely adjacent a sidewall of the lower frame to prevent the ingress of material therebetween.