In recent years, various physiological functions of salmon milt extract, which consists of nucleic acid and nucleoprotein, have been reported. The objective of this study is to analyze the physiological function and its mechanism of salmon milt extract (NG) on nematodes (C. elegans). The wild type nematode N2 strain was bred on the plate containing of NG for four days, and its body length increased depending on NG concentration. When nematodes were bred with NG for a longer period, average lifespan was increased, and survival rate was increased by up to 20%. Generally, the movement of nematodes decreases with longer breeding period (i.e. aging). Analysis of movement (both gross thrashing movement and local pumping movement) showed that NG suppressed this decrease f movement with aging. Furthermore, the deease of survival rate by heat stress and oxidative stress was suppressed by NG administration. Nile Red staining analysis showed that fat accumulation varied depending on the concentration of NG. RT-PCR analysis revealed that the mRNA expression levels of the stress resistance genes sod-3 and sod-4 were increased. These results indicated that NG administration increased the expression of stress-tolerance-related genes, promoted stress tolerance, increased movement and prolonged lifespan in nematode