Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by selective loss of motor neurons (MNs). About 20% familial cases of ALS (fALS) carried the Cu, Zn-superoxide dismutase (SOD1) gene mutation, which plays a crucial role in the pathogenesis of fALS. There is evidence suggesting that macroautophagy can degrade mutated SOD1 in vitro. To investigate whether the mutant SOD1 can induce macroautophagy in vivo, we examined the LC3 processing in spinal cord and the activation status of macroautophagy in MNs of SOD1(G93A) transgenic mice at different stages. Our data demonstrated that autophagy was activated in spinal cord of SOD1(G93A) mice indicating a possible role of macroautophagy in the pathogenesis of ALS.