The impaired anabolic response of muscle protein synthesis in response to insulin and amino acids, during ageing, has previously been shown to be associated with blunted S6K1 activation (Guillet et al., 2004). Long-chain n-3 fatty acids (LCn-3 FAs) have previously been shown to increase protein anabolism in young animal models (Gingras et al., 2007). However, reports in ageing skeletal muscle are, at present, limited. The present study aimed to investigate whether the LCn-3 FAs, Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), produce a positive effect on anabolic signalling pathways in ageing skeletal muscle. To test this hypothesis, 31 Hooded Lister male rats aged between 13-15 month-old were fed for 2 months with either control (n=15) or EPA and DHA enriched supplement (n=16) diets. Body mass, fat mass and lean mass were measured at baseline, 1 and 2 months of the study. Soleus and Longissimus dorsi muscle samples were then collected after 6h infusion with dextrose and amino acids. Prior to infusion, the rats were acclimatised to a restraining tube over 5 days. Total and phosphorylated amounts of Akt[Ser473], mTOR[Ser2448], 4EBP1[Thr37/46], and p70s6k[Thr389] were measured by western blotting. Data were analysed by two-way ANOVA and independent t-tests. Data are expressed as mean ± S.E.M. Both treatment groups had similar food intake (16.6 ± 0.4 g/d), weight gain (625.6 ± 5.5 g to 650.6 ± 6.5 g, p>0.05) and increase in total fat mass (95.3 ± 3.3 g to 132.0 ± 3.5 g, p>0.05). Overall rats showed a small decrease in lean body mass (531.3 ± 5.9 g to 516.1 ± 6.1 g, p>0.05), over the study period, with a tendency for this decrease to be greater in the control group (-18.8 ± 5.1 g. vs -9.7 ± 3.0 g., p=0.10). Dietary LCn-3 FAs was not found to have any effect on the anabolic signalling pathways in the soleus. However, in longissimus dorsi, LCn-3 FAs produced an increase (44.6 ± 16.4 %, p=0.04) in p70s6k[Thr389] phosphorylation, the key protein in the initiation step of protein translation, with no changes in phosphorylation of Akt[Ser473], mTOR[Ser2448] and 4EBP1[Thr37/46]. This study has demonstrated that the LCn-3 FAs, EPA and DHA, may conserve the loss of lean muscle mass observed during ageing via p70s6k activation, independently of Akt, mTOR and 4EBP1.