The hot deformation characteristics of a FeCrMnN austenitic stainless steel containing 0.28 wt.% nitrogen (N) was investigated by hot compression tests using a Gleeble simulator in the temperature range of 800-1200 degrees C and at constant true strain rates of 0.01-10 s(-1) with all specimens deformed to similar to 0.9 true strain. The influence of deformation conditions on microstructural mechanisms and phase transformations was characterized. A processing map based on dynamic materials modelling (DMM) was designed and interpreted for predicting the domain of stable flow for safe, defect-free hot deformation. The results revealed the occurrence of dynamic recrystallization (DRX) in a domain extending over the temperature and strain rate ranges of 1100-1200 degrees C and 0.1-1 s(-1), respectively, with the efficiency of power dissipation (eta) of 45-55 %. Decreasing temperature and increasing strain rate led to a reduction in DRX grain size following microstructural reconstitution. Another small deterministic domain of 820-1000 degrees C and 0.01-0.05 s(-1) was identified showing occurrence of partial DRX in shear bands leading to formation of a mixed microstructure. The instability criteria delineated the regime of unstable flow covering a large part of the processing map extending over low temperatures (800-950 degrees C) and high strain rates (0.1-10 s(-1)) that must be avoided during processing.