Tilmicosin is tylosin phosphate synthesis from the macrolide antibiotics, but its antibacterial activity is much stronger than tylosin.

Tilmicosin is produced semi-synthetically and is in the macrolide class of antibiotics. It has an invitro antibacterial spectrum that is predominately Gram-positive with activity against certain Gram-negative microorganisims. Activity against several mycoplasma species has also been detected.