This study was performed to analyze in vitro and in vivo activities of LCB01-0183, a new oxazolidinone, against clinical isolates of bacteria. In vitro antibacterial activity of LCB01-0183 was tested by the two fold agar dilution method. In vivo activity of LCB01-0183 was determined against systemic infections in mice. LCB01-0183 showed most potent activity among the test compounds against clinical isolates of Gram-positive bacteria. Furthermore, the protective activity of LCB01-0183 was very effective against systemic infections in mice by oral or subcutaneous administration. In time kill study, LCB01-0183 showed a bacteriostatic activity during 24 hours. LCB01-0183 had potent in vitro and in vivo activity against Gram-positive bacteria including drug-resistant strains.