Postmortem changes were examined in myofibrillar proteins of M. pectoralis, M. sartorius and M. soleus from Korean native chickens(KNC) and commercial broilers. Purified myofibrils were prepared from the muscles after 0, 3, 6, 12, 24, 48, 72 and 120 hours of post mortem storage at 4℃. SDS-PAGE results showed that 30kDa and 32kDa components appeared earlier in the M. pectoralis than in the M. sartorius and M. coleus from KNC and broilers. These components were observed after 12 hours post mortem in all M. pectoralis. Titin I disappeared after 12 hours post mortem in M. pectoralis from KNC, earlier than that of broilers. In M. sartorius, thin II appeared after 6 hours post mortem in KNC, earlier than that of broilers, and thin I disappeared after 120 hours of storage. Titin II appeared after 24 hours post mortem in M. Soleus from KNC and broilers. Among all the samples studied, the post mortem changes in M. Pectoralis was the fastest and those changes in M. coleus was the slowest. The molecular weight of the titin in M. coleus and M. sartorius is larger than that of M. pectoralis from KNC.