The influence of the gas pressure and the RF discharge power on sputtered Ti and W atom concentrations in r.f. magnetron sputtering has been studied. Ti and W spatial densities were experimentally determined by optical spectroscopic measurements, As the discharge pressure increases in the range of 0.667 Pa to 5.33 Pa, the sputtering species are thermalized. Consequently their densities in the discharge increase with pressure. Owing to their weaker mass value, Ti atoms are faster thermalized than W atoms. The concentrations in the plasma of sputtered species increase quasi-linearly with the RF power as the impinging argon ion energy. Experimental results are in good agreement with those obtained with a transport model based on a particle in cell Monte Carlo method. The simulation uses a subcosinus law for the ejection angular distribution and a Thompson's theoretical distribution of the energy for atoms sputtered from the cathode surface. Collisions between background gas atoms and ejected species are described with a Born-Mayer interaction potential. The transport model will be useful for predicting the sputtered atom flux on every surface in contact with the discharge.