Abstract
We probe the stau-neutralino coannihilation region of the parameter space within the framework of minimal SUGRA models at a photon-photon collider. The most favorable signals of SUSY is stau-pair production where the small mass difference between the stau and neutralino the in the coannihilation region is 5~15GeV.The standard model background is dominated by W-pair production. We propose a series of cuts which reduce this background.