Market requirements for business, commuter and unmanned aircrafts generally lead to compact, low cost and fuel efficient small aero-engines. Design and technology requirements for small aero-engines, compared to the large ones used on most commercial aircrafts, are quite challenging. Resulting compressors and turbines normally have high pressure ratio and stage loading, small aspect ratio airfoils, transonic Mach numbers, low Reynolds numbers and high turning blades. The small size of the turbomachinery adds another complexity in terms of the stringent structural requirements to achieve the desired target life as well as the manufacturing, production and assembly challenges associated with small aero-engines. This presentation will attempt to point out these challenges and solutions based on our own experience working in the area. Thanks to the innovative key technologies we stored over the past three decades, (including the non-shrouded wider chord/swept fan blades, advanced highly-loaded mixed-flow compressor, low-emission reverse flow combustor, highly-loaded un-cooled turbine, aggressive inter-turbine transition duct and the novel lobed-mixer exhaust system,) a brand-new, compact, fuel efficient small aero-engine rated at a take-off thrust of 1000 daN was developed.