The use of atomistic Kinetic Monte Carlo method was explored to examine the influence of sulfur poisoning on CO adsorption on Pd(100) surface. The model explicitly incorporates key elementary processes such as CO adsorption and CO desorption including diffusion of surface CO and S species. Relevant energetic and kinetic parameters were derived using information calculated from density functional theory as a starting point. Kinetic Monte Carlo simulation was performed to determine relevant observables such as CO saturation coverage as a function of amount of preadsorbed sulfur and to predict temperature programmed desorption spectra.