Experimental data on performance and cooling from sea level and altitude firing tests of fluorine/oxygen mixtures with light-hydrocarbon fuels are presented. The majority of the work has been oriented toward pressure-fed rocket applications, with testing at 5000-lb vacuum thrust and 100-psia chamber pressure. Work in progress is at chamber pressures of 250 and 500 psia, being oriented toward pump-fed rocket applications. High delivered specific impulse levels have been demonstrated. One problem, apparently unique to these propellants, is that performance at the optimum mixture ratio is extremely sensitive to incomplete mixing.