The electron swarm parameters, namely electron mean energy, drift velocity, effective ionization coefficient and limiting values of number density reduced electric fields, E/N, are calculated in CF 4 +Ar mixtures for various CF 4 concentrations that vary from 2 to 100% over a range of E/N from 50Td to 600Td by solving Boltzmann's equation. In this study Boltzmann's equation was solved using finite difference method under steady-state Townsend condition. One of the most important results of this study indicated that at higher E/N values inelastic processes due to argon began to control the swarm energy thus leading this binary mixture act essentially like pure argon.