The average burning rates of composite solid rocket propellant were measured in acceleration fields up to 2000 times the standard acceleration of gravity. The acceleration vector was perpendicular to and into the burning surface. Propellant strands were burned in a combustion bomb mounted on a centrifuge, and surge tanks were employed to ensure essentially constant pressure burning at 500, 1000, and 1500 psia. The burning rates of both aluminized and non-aluminized composite propellants were found to depend on acceleration. The effect of acceleration on burning rate was found to depend on the burning rate of the propellant without acceleration, aluminum mass loading, and aluminum mass median particle size. The relative burning rate increase was found to be greater for slow burning propellant than for faster burning propellants. The experimental results are compared to the analytical models proposed by Crowe for aluminized propellants and by Glick for non-aluminized propellants. The results indicate that these models do not adequately predict the observed relative burning rate increase with acceleration, and hence, that more complex modeling will be required to explain the observed acceleration effect.