A method for forming tires by the use of a tire-forming machine having a drum bladder and a turnup bladder. An organic halogen compound having in the molecule thereof a ##STR1## bond, in which X represents a halogen atom, is applied to the surfaces of the drum bladder and turnup bladder of the machine to form a layer of the organic halogen compound, whereby unvulcanized rubber for tires is prevented from sticking to said bladders during the formation of tires form the unvulcanized rubber.