Hot deformation behavior of 30Mn-0.5C-3.7Al-4Si TWIP steel using hot compression test and establishment of processing map was investigated in this study. Cylindrical specimens were used for hot compression tests at temperatures ranging from 750 to 1000 o C and the strain rate range of 0.001-0.5s ? 1 . Work hardening behaviors of samples were investigated by strain hardening curves. Microstructures evaluation procedures, such as optical microscope, SEM and EBSD were conducted on the specimens after the hot compression tests. Dynamic recrystallization mechanisms during hot deformation were investigated. It was shown that increasing temperature promoted dynamic recrystallization. Increasing strain rate caused to increasing dynamic recrystallization and increasing final grain size due to increasing sites for nucleation and decreasing growth rate of grains during dynamic recrystallization. Effect of hot deformation parameter such as temperature and strain rate on texture of samples shown that with increasing temperature in low strain rates, cube component, that is recrystallization texture component, developed but increasing strain rate caused to formation of copper component due to occurrence of strain induced migration boundary mechanism in recrystallization of grains. Then, processing maps of hot deformation of the steel at the selected strains of 0.5 and 0.6 were developed. The generated processing maps indicated that there were only one unstable region and two stable regions in which dynamic recrystallization occurred. In the unstable region, formations of cracks caused to instability. Finally, an optimum hot working condition for the TWIP steel was predicted at a temperature of about 1000 o C and the strain rate 0.1s ? 1 . Key words : TWIP steel; Hot deformation; Processing map