The purpose of this study was to investigate condensed-phase particle growth in a rocket nozzle by particle collision and coalescence. An analysis is developed wherein it is assumed that the more rapidly moving smaller particles collide and coalesce with the larger ones, forming even larger particles and increasing the mass-median particle diameter. The results of a series of calculations are presented which predict particle growth in particular motor-nozzle configurations and indicate the effect of pressure level, nozzle scale, aluminum loading, and initial particle size distribution on resulting particle size. Calculations were also performed to determine particle growth upon passage through a normal shock wave. Comparisons are made between the calculated mass-median diameters and those measured on particles collected from solid propellant motor exhausts.