Effects of Modified Atmosphere Packaging (MAP) in combination to UV-C radiation on rainbow trout fillets were examined. The samples were submitted to two treatments: (T1) aerobic package; (T2) MAP+UV-C radiation (80% CO2/20% N2; 106.32mJ/cm2) and were analyzed daily for microbiological (mesophilic and psychrotrophic count) and chemical (biogenic amines) parameters. MAP+UV-C radiation (T2) promoted lag phase formation and lower number of colonies in the stationary phase as well as retarded cadaverine production during storage time. MAP+UV-C radiation retard microbial growth and delay chemical changes enhancing the shelf life of rainbow trout fillets by at least twice.