Absolute total cross sections for collisional dissociation and charge transfer have been measured for collisions of H-3(+) and D-3(+) with He, Ar, Xe for projectile energies ranging from 15 to 400 eV. The cross sections for collision-induced dissociation of H-3(+) into H++H-2 or H+H-2(+) are a few Angstrom(2) and exhibit a weak target dependence. It is suggested that the charge transfer cross sections, which vary markedly with target species, are due primarily to proton transfer to the rare gas target rather than electron transfer for the target. At the lower collision energies, proton abstraction is favored over deuteron abstraction for the He and Ar targets.