The chain transfer reaction was examined in the anionic telomerization of butadiene with n-BuLi as the initiator, potassium para-methylphenoxide (ROK) as the novel promoter, mixed xylene as the transfer agent as well as a solvent in the presence of diglyme as the polar modifier. Effects of ROK, diglyme, and the polymerizing temperature were studied. It was demonstrated that they all promote the chain transfer reaction. The relative constant of chain transfer to the solvent was also calculated. (C) 2005 Wiley Periodicals, Inc.