It was reported that an accumulation of Sadenosyl-L-methionine increases production of actinorhodin in Streptomyces lividans and induces antibiotic biosynthetic genes. We also obtained the same result in Streptomyces coelicolor A3(2). Therefore, in order to identify proteins changed by the addition of S-adenosyl-L-methionine in S. coelicolor A3(2), LC/MS/MS analyses were carried out. Thirteen proteins that were not observed in the control were found.