Titanium and its alloys are currently considered as successful biocompatible materials because titanium made implants become easily, structurally and functionally, connected to biological systems. As far as biological systems is concerned, antibacterial activity for medical implants are worth of interest to prevent inflammation at implant site. In this study RF cold plasma is employed as potential technology to prevent or reduce bacterial activity on Ti samples. Several plasma parameters are investigated for finding the best antibacterial process conditions against Escherichia coli 32. Main results of this investigation show that high antibacterial activity is exhibited by Ti samples in several experimental set-ups. In addition, the antibacterial activity detected at same level of previous, 16 days after the treatment suggests the effectiveness of the plasma surface modification. Finally, an attempt is made to correlate antibacterial effect with plasma treated titanium surface energy and plasma parameters.