The Al-Pd alloy phase diagram was revised in the compositional range of 0-40 at.% Pd. The existence of the λ, γ and δ phases reported earlier was confirmed. The γ-phase was found to be a low-temperature phase isostructural to Al 2 1 Pt 8 (I4 1 /a; a=1.2998(4), c=1.0729(7) nm) and to be formed at 27.5 at.% Pd. In addition, two structurally related high-temperature orthorhombic phases were observed close to this composition. One, at 25.5-26.9 at.% Pd, is associated with the Al 3 Pd reported earlier in the literature and has lattice parameters of a=2.35, b=1.68 and c=1.23 nm, the other, at about 28 at.% Pd has lattice parameters of a=2.35, b=1.68 and c=5.70 nm. The transition temperatures were specified from the thermal analysis measurements.