Resistance exercise training results in a progressive increase in muscle mass and force production. Following an acute bout of resistance exercise, the rate of protein synthesis increases proportionally with the increase in protein degradation, correlating at 3 hours in the starved state. Amino acids taken immediately before or immediately after exercise increase the post exercise rate of protein synthesis. Therefore a protein that controls protein degradation and amino acid sensitivity would be a potential candidate for controlling the activation of protein synthesis following resistance exercise. One such candidate is the class 3 phosphatidylinositol 3OH -kinase (PI3K) Vps34. Vps34 controls both autophagy and amino acid signalling to mTOR (mammalian target of rapamycin) and its downstream target p70 S6 kinase (S6K1). The aim of this study was to determine the role of Vps34 in mTOR activation following resistance exercise. As the prevalence of Vps34 has yet to be described, we determined first its tissue distribution. Vps34 is a ubiquitous protein with high levels in brain and skeletal muscle. Interestingly, Vps34 levels were highest in muscles with a greater percentage of slow oxidative fibres. To determine whether Vps34 is modulated by exercise. Vps34 and S6K1 activity were measured in the distal hindlimb muscles of rats 30 mins, 3 hours, 6 hours and 18 hours after acute unilateral resistance exercise with the contralateral muscles serving as a control. In the tibialis anterior (TA) we found a 366.30±112.08 (p=0.037), 124.67±15.96 (p=0.012) and 129.18±0.1-fold (p=0.013) increase in S6K1 activity at the 30 min, 3 hour and 6 hour time points respectively. This was in contrast to the soleus, which showed no significant increase in S6K1 activity at any time point and the plantaris, which only showed a 33.14±2.29 (p<0.001) and 47.00±6.65 (p=0.02) percentage increase in activity at the 30 minute and 3 hour time point respectively. Unlike S6K1, Vps34 activity increased only at the 3 and 6 hour time point in the TA muscle showing a 100.86±18.19 (p=0.01) and 36.01±8.79 (p=0.02) percent increase respectively. A 24.48±7.92 (p=0.02) percent increase of activity was observed in the plantaris 3 hours post exercise giving a similar pattern of activity between Vps34 and S6K1. S6K1 activity was still high 18 hours post exercise when Vps34 had returned to basal in the TA. The increase in Vps34 activity we observe at 3 hours correlates with the increase in protein degradation and synthesis following resistance exercise. We propose that the increase in Vps34 activity results in an increase in the intracellular pool of free amino acids activating mTOR and sustaining the high activity of S6K1.