A supporting rail fitting for a drawer pull-out guide for frame furniture having at least one vertical and one horizontal frame member. The supporting rail is secured to the frame at the front. A mounting plat capable of being secured to the vertical frame member and having a securing web is provided. Securing means, such as screws, project through the securing web. The mounting plate has at least one stop web which extends at right angles to the securing web and in the mounted state lies laterally against the frame member. Further, the mounting plate is provided with an anchoring web which protrudes from the frame member and to which the supporting rail can be coupled.