Two ternary phases, designated τ4 and τ5, were revealed in Al–Ti–Pt. The τ4-phase with equiatomic composition (i.e., AlTiPt) was found to have a hexagonal structure with a=4.3908(9) Å and c=5.4823(10) Å (space group P63/mmc), and the τ5-phase, forming in a compositional range between ∼Al14Ti58Pt28 and Al21Ti63Pt16, has a tetragonal structure (possible space groups P42nm, P-4n2, and P42/mnm). The refined lattice parameters for Al15Ti60Pt25 are a=9.7019(20) Å and c=5.0231(13)Å.