Performance calculations for the liquid hydrogen-liquid ozone propellant are presented for combustion pressures of 150, 300 and 600 pounds per square inch, oxidizer to fuel mass ratios from 1.0 to 39.638 and pressure ratios from one to 4000. For the combustion process, data are presented for the temperature, enthalpy, composition, ertropy, specific heat at constant pressure and volume, the average molecular weight of the products, and the isentropic exponent. For the expansion process, in addition to the foregoing quantities, data are presented for the specific impulse, coefficient of thrust, characteristic velocity, exit Mach number and ratio of exit area to throat area. The calculations have been carried out for frozen and equilibrium expansion processes. The maximum specific impulse corresponding to an exit pressure of one atmosphere has been calculated to be 408.3, 380.6, and 343.7 ibf-sec/ib (subscript m) for combustion pressures of 600, 300 and 150 psia, respectively. These values are compared to those of several other propellants operating under similar conditions. The result of this comparison indicates that the specific impulse of the hydrogen-ozone propellant is greater than that of the hydrogen-ozone propellant is greater than that of the hydrogen-fluorine propellant. The hydrogen-fluorine propellant is one of the most powerful propellants known. A maximum specific impulse of 508.7 Ib-sec/lb (subscript m) is obtained at a combustion pressure of 600 psia, an oxidizer-fuel ratio of 5.556 and a pressure ratio of 4000.