The push toward higher specific fuel consumption and smaller, lighter packaging for reduced-cost aerospace gas turbine engines has resulted in large increases in engine operating pressures and temperatures, as well as major efforts to reduce gas path losses and increase component Efficiencies. This is a tread that is expected to continue, and as a result, thermal management of the hot engine section, including the fuel nozzle, combustor, and turbine, has emerged as a critical technology area requiring further research and development. For the fuel injection system, nozzle thermal management, turndown ratio, and atomization performance while maintaining correct combustor aerodynamics and low pollutant emissions are the most important performance features that necessitate optimization. Complex and expensive heat-shielded designs are often required to reduce nettle wetted-wall temperatures and prevent the formation of carbonaceous deposits within the fuel delivery passages. Optimization of designs using current computational methods is limited in capability and expensive. Significant advances infuel injection concepts, physical understanding, and computational methods are required to merl these increasingly demanding combustor requirements, with configurations at or below current cost levels. Five injector designs are presented, which include an advanced hybrid air blast (HAB) atomizer, a ball direct-injection (LDI) concept and three lean prevaporized premixer (LPP) designs that exemplify advanced fuel injection technology and ideas to address the challenges of next-generation gas turbine combustors.