Low thawing rates affects the quality of the product, which necessitates the use of new thawing technologies. In this study, the effect of alternating magnetic field (MF) (1-80 Hz) on the thawing rate, physicochemical properties, protein denaturation, and structure of rainbow trout fillet was studied and compared with refrigerator thawing (RT) (4 °C). Thawing time remarkably decreased in MF thawing as compared to RT. The results revealed that the water holding capacity of RT was significantly lower than that of MF, which was consistent with the results of structural investigation characterized by Scanning electron microscopy. Particle size distribution, Fourier transform infrared spectroscopy, and Differential scanning calorimetry indicated that MF could unfold and aggregate the protein structure at 40 and 80 Hz. The findings of this study indicated the potential of the MF in accelerating the thawing process. However, more studies are needed to clarify all aspects of the process.