Abstract: A portable modular safety rail (20) is taught for protecting workers during building construction and remodeling. The invention in the preferred embodiment consists of two upright stanchions (22) having a flat mounting plate (36) on the bottom which is removably attached with fasteners onto a building. A number of connection members, in the form of round rings (46), protrude from the sides of each stanchion. Two adjustable length rails (56) that are rigid and telescope together engage the connection members on each end with pivotal attachment means consisting of safety snap pins (68) that fasten the rails with the assembly forming the safety rail module. The safety rail module may be horizontal when the stanchions are attached to a level surface or may be angled to accommodate stairs. A second embodiment substitutes chains (64) instead of the adjustable telescoping rails.