Pleuromutilins were discovered as natural-product antibiotics in 1950. The modifications of pleuromutilin lead to the successful development of veterinary medicines such as tiamulin and valnemulin. Retapamulin became the first pleuromutilin approved for use in human skin infections. Recent advances have led to the synthesis of pleuromutilins that combine potent antibacterial activity with favorable pharmaceutical properties, and three new pleuromutilins, BC-3781, BC-3205 and BC-7013, have entered clinical trials. In this review, the key pleuromutilin derivatives, as well as related novel derivatives during 2009-2013, and its antibacterial activities, are presented. Moreover, the antibacterial and resistance mechanism are discussed.