The ethylene-propylene diene monomer (EPDM) rubber is an important material for rocket engine technology due to its thermal and mechanical characteristics, The improvement of the adhesion characteristics of EPDM on other kinds of polymers, using plasma technology, has been the major subject of many research works carried out during the last years. In this work, the EPDM surface activation process was carried out in a reactive ion etching reactor (RIE) operated at 13,54 MHz using pure oxygen and a gas mixture of argon and oxygen. These essays were performed varying the process pressure from 70 mTorr to 1000 mTorr, process time from 1min to 10min and RF power input from 50W to 200W. The surfaces of the treated samples were analyzed by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR). The evolution of the C-OH, and C=O and R-0 chemical groups were observed. as a function of the plasma process parameters. The analysis of the IR spectra showed that there are experimental condition of the process in which the production of new radical groups on this rubber surface is maximized.