Studies on the functionality of muscle proteins in gelation mechanisms of structured meat products during the last three decades are briefly reviewed. Among muscle proteins, myosin is primarily the most important protein for gelation, whereas actin plays a complementary role in gelation when it coexists with myosin. The combined data of gelation and denaturation indicate that the gelation of myosin consists of two stages: (1) aggregation of myosin molecules through their heads at 43℃; and (2) cross-linking reaction due to helix-coil transition of the tail portion of the molecules at 55℃. In the myosin-actin system, a system consisting of 80% of free myosin 20% of actomyosin complex on heating yielded a gel with a maximum strength. The reinforced network structure of myosin by actomyosin complex is completed at 60-65℃.