Using molecular dynamics simulations, the adsorption of He gas on the Ag nano clusters were investigated as a function of pressure, temperature and diameter of nanoclusters. We have calculated the average interaction energy between the gas atoms and the Ag nanoclusters, adsorption constant and enthalpy of adsorption for all of the Ag nanoclusters. Results show that the adsorption constant, the value of average interaction energy and the enthalpy of adsorption decrease when cluster size increases. (C) 2014 Elsevier B.V. All rights reserved.