The results of a transmission electron microscopy study on the crystal structures and morphologies exhibited by each of the phases in a set of four Al-rich Al-Y-Ni alloys which contain 1.7–4.5 at. % Y and 3.5–10.1 at. % Ni are presented. It is shown that each alloy contains fcc-Al, a binary Al3Ni or Al3Y phase (depending on alloy composition), and a ternary phase. The same ternary phase was found in each alloy and this was found to correspond to a new phase Al19Ni5Y3 (Cmcm, a=0.4025 nm, b=0.799 nm and c= 2.689 nm, Al19Ni5Gd3 structure type). In many cases, the ternary particles also contain embedded slabs of the equilibrium Al23Ni6Y4 phase. This phase mixture did not decompose even after extended annealing.