We gamma-irradiated to natural casings from lamb and pork to improve sanitary quality and microbiological shelf stability of sausage stuffed in animal intestine-induced natural casing from lamb and pork. The microbial changes of irradiated casings and the microbial growth of the sausages with gamma-irradiated natural casings were observed. Population of total aerobic bacteria was decreased by gamma irradiation, dependent upon the irradiation dose. The number of microflora in lamb and pork casings was reduced by about 5.5 log cycle at 5 kGy. Population of total aerobic bacteria of sausages stuffed in non-irradiated lamb and pork casing was about 3.6 log CFU/g after just manufacture and was about 7 log after 10 day storage. However, population of total aerobic bacteria of sausages with 3 kGy-irradiated and 5 kGy-irradiated casings was 2.48 and 0.32 log in lamb, and 2.78 and 0.60 log in pork, respectively. Gamma irradiation to animal intestine- induced natural casings was effective and thus, can be used for enhancing shelf life of final products due to reduction of the number of contaminated microflora.