Abstract: The biosynthesis of spiramycin (SPM) is susceptible to carbon and nitrogen catabolic repression, as well as end product feedback regulation. In this paper, the study of the effect of various factors on the biosynthesis of SPM using resting cell system is presented. It was found that acetate, pyruvatc, glycerol, butyl alcohol, mcthioninc, histidine, leucinc, and valine have favorable effects, while NH_4~+ with concentration higher than 0.2% has an adverse effect on the biosynthesis of SPM. Besides, the biosynthesis of SPM is also susceptible to, its end product regulation. Both NH_4~+ repression and end product inhibition can be released by the addition of suitable amount of KH_2PO_4 at proper incubation period. With the help of chloramphenicol, it was shown that the biosynthcsis of SPM begins at 30h after inoculation.