Against the background of increasing environmental concerns, analytical modelling and experimental tests on low-NOx hydrogen combustors for aero engines have been conducted-within the Euro-Quebec Hydro-Hydrogen Pilot Project (EQHHPP). This project is jointly supported by the European Union and the Government of Quebec. This is a four year program started in 1992; the objectives are to establish the NOx reduction potential and to provide design guidelines for later development of real aero engine combustors. The paper discusses the findings from phase III.0-2 (demonstration phase) of this program (DASA Airbus, PWC, DASA, DASA MTU, DLR Final Report on the NOx Reduction Concept EQHHPP Phase III.0-2 "Potential Use of Hydrogen in Air Propulsion", December 1996). Various candidate fuel preparation concepts for lean hydrogen combustion with and without fuel/air premixing have beer evaluated in a generic can type combustor at Pratt and Whitney Canada (PWC). Significant reduction in NOx emissions at simulated representative engine conditions has been achieved. Two concepts were then selected for further investigation in a research type combustion chamber which represents a typical 60 degrees sector of a modern annular combustor. A test rig has been built by MTU especially for these tests. Steady state testing is being performed at Daimler-Benz Aerospace. Further tests to study the transient behaviour have been conducted by United Technologies Research Centre (UTRC). In addition; kinetic modelling was performed at Deutsche Forschungsanstalt fur Luft-und Raumfahrt (DLR) and PWC to provide a useful design tool for low-NOx hydrogen combustors.