We report quantum-mechanical close-coupling calculations for rotational state resolved cross-sections for p-H-2, + HD collisions. The low temperature limit of p-H-2 + HD is investigated, which is of significant astrophysical interest in regard to the cooling of primordial gas and the interstellar media. Sharp resonances have been reproduced in the cross-sections of some transition states at very low kinetic energies, E-kin similar to (10(-4)-10(-5)) eV. (c) 2007 Elsevier B.V. All rights reserved.