The ethylene oxide sterilization process control should take into account several parameters, so that only the biological monitor can integrate in all of them, presenting a biological challenge similar to the product under sterilization conditions. The authors evaluated spore resistance on several different carriers: paper, aluminum foil and plastic. The influence was studied through the challenge of sub-lethal cycles, followed by the lethality study and the D-value calculation. There was a significant statistical difference in spore resistance between paper and plastic carriers.