Abstract: A floor joist hanger for use with poured concrete walls that allows floor joists to be easily suspended from wall to wall to thereby support a floor, ceiling, or roof of a structure. The floor joist hanger has two parallel and opposing side members that are inserted into vertical slits that have been cut into an insulated form. The floor joist hanger is provided with at least one elongated slit for receiving a strap for securing a floor joist to the floor joist hanger. The floor joist hanger is further provided with a cross-support member extending between the side members. The cross-support member has an upper surface for engaging a bottom surface of a floor joist. The floor joist hanger is anchored to the wall by concrete poured into the insulated form and allowed to cure.