We calculate the inelastic mean free path (IMFP) for small metal particles based on the plasmon model for free electron gas confined in small sphere with radius a. The IMFP decreases with the radius a smaller than about 100Å, and the rate of the decrease depends on the bulk plasmon energy ωp. We furthermore discuss the coordination numbers obtained from the EXAFS curve fitting method for small Ag particles. We find the importance of the size dependent IMFP for EXAFS analyses in order to obtain reliable coordination numbers in nanoparticles.