This rebar chair has a body with four legs between which there are defined two intersecting passages for simultaneously receiving the intersecting portions of two rebars normal to each other. The rebars are suspended by a fastening wire or supported by an auxiliary chair below said body. The legs forming one of the passages have a uniform spacing and are adapted to closely straddle the rebar extending through the same. The legs of the second passage flare downwardly so that their spacing progressively increases from the body to the free ends from a spacing smaller than to a spacing greater than the uniform spacing between the legs of the first passage. The chair is positively located and stabilized by the intersecting rebars. A saddle is formed on the top of the body for simultaneously supporting a third rebar. The spacing between the faces of the legs forming a first passage is uniform from the body to the free ends of the legs while the spacing between the faces of the legs forming the other right angle passage increases from the body to the free ends of the legs in such a manner that depending on the orientation of the chair with respect to the rebars the same can be positioned at two adjusted distances from the bottom of the concrete form.