Abstract: A rack assembly having a plurality of support posts, brackets extending from individual support posts, and a bracket rail extending between two or more brackets and capable of supporting goods. An outer plate portion of each support post is formed with a plurality of vertically spaced apart engagement holes. Each bracket has engaging projections adapted to be received into the engagement holes, engaging pawls extending from the respective engaging projections and engageable with respective edges of the engagement holes, and a plate portion abuttable to the outer surface of the support post. The bracket can be mounted to the support post by inserting the engaging projections into corresponding engagement holes at the erection site to allow the engaging pawls to engage the edge of the engagement holes. Simultaneously, the slip-off preventive projection of the bracket is inserted into the slip-off preventing hole in the side plate portion of the support post.