The aim of this study is to investigate the effects of working fluid (nitrogen, argon and oxygen) on the performance of adsorption cryocooler in the range 77-100 K. A thermodynamic model of adsorption cryocooler with two-stage compressor has been constructed. The model is based on quasi-static conditions without considering the temperature profiles and pressure drops across the compressor. It is then analyzed with an optimization toolbox to determine the optimum operating conditions to obtain the optimum performance of adsorption cryocooler. The Coefficient of Performance (COP) for each working fluid in the range 77-100 K is obtained and compared. It is found that working fluid has larger effects on adsorption compressor than on cold stage, and the optimum selection of working fluid depends on the operating parameters. (C) 2014 Elsevier Ltd. All rights reserved.