  We present a first and extensive study of threshold resummation effects for
supersymmetric (SUSY) particle production at hadron colliders, focusing on
Drell-Yan like slepton-pair and slepton-sneutrino associated production. After
confirming the known next-to-leading order (NLO) QCD corrections and
generalizing the NLO SUSY-QCD corrections to the case of mixing squarks in the
virtual loop contributions, we employ the usual Mellin N-space resummation
formalism with the minimal prescription for the inverse Mellin-transform and
improve it by resumming 1/N-suppressed and a class of N-independent universal
contributions. Numerically, our results increase the theoretical cross sections
by 5 to 15% with respect to the NLO predictions and stabilize them by reducing
the scale dependence from up to 20% at NLO to less than 10% with threshold
resummation.
