The rigor-mortis progress of cultured olive flounder spiked at the brain started much faster than that of wild one. They attained full rigor state after 30 hrs at $0^{circ}C$, 36 hrs at $5^{circ}C$ and 50 hrs at $10^{circ}C$ in the cultured flounder, while after 36 hrs at $0^{circ}C$, 50 hrs at $5^{circ}C$, and 60 hrs at $10^{circ}C$ in the wild. ATP concentration in the muscle was around $5.9mu mol/g$ for wild and $6.2mu mol/g$ for cultured flounder. ATP breakdown progressed rapidly in $0^{circ}C$ samples, followed by $5^{circ}C$ and $10^{circ}C$ samples. $Mg^{2+}$-ATPase activity of myofibrillar protein in the presence of 0.25mM CaCb was higher in cultured myofibri1lar protein than in wild one. $Mg^{2+}$-ATPase activities of myofibrillar protein increased during storage in samples stored at $0^{circ}C$ and $5^{circ}C$ while decreased in samples stored at $10^{circ}C$. The level of breaking strength of muscle immediately after death was higher in the wild muscle than in the cultured muscle. The breaking strength reached maximum level at 10 hrs after death in both samples.