A serious consequence of sepsis is acute lung injury, whose severity is particularly impacted by the age of the patient. AMP-activated protein kinase (AMPK) is a crucial regulator of cellular metabolism, which controls mitochondrial biogenesis and autophagy. Here, we investigated the effect of pharmacological activation of AMPK with A769662 on lung injury by using a model that would preferably mimic the clinical condition of adult patients. Male C57BL/6 retired breeder mice (7-9 months old) were subjected to sepsis by cecal ligation and puncture (CLP). Mice received vehicle or A769662 (10 mg/kg) intraperitoneally at 1 h after CLP. At 6 h after CLP, vehicle-treated mice exhibited severe lung injury and elevation of plasma pro-inflammatory cytokines when compared with control mice. At molecular analysis, lung injury was associated with downregulation of AMPKα1/α2 catalytic subunits and reduced phosphorylation of AMPKβ1 regulatory subunit. Treatment with A769662 ameliorated lung architecture, reduced bacterial load in lung and blood, and attenuated plasma levels of interleukin-6. This protective effect was associated with nuclear phosphorylation of AMPKα1/α2 and AMPKβ1, increased nuclear expression of peroxisome proliferator-activated receptor γ co-activator-α and increased autophagy, as evaluated by the light-chain (LC)3B-I and LC3B-II content, without changes in sirtuin-1 cellular dynamics. Treatment with A769662 alone or in combination with the antimicrobial agent imipenem (25 mg/kg) increased survival rate (29% and 51%, respectively) when compared with vehicle treatment (10%) at 7 days after CLP. These data suggest that pharmacological activation of AMPK might be a beneficial approach for the treatment of sepsis in adult population.