The carotid bodies play a critical role in initiating compensatory ventilatory responses to hypoxia. However, the complete mechanism by which hypoxia excites the oxygen-sensing carotid body type 1 cells has not been fully defined. We have previously proposed that the enzyme adenosine monophosphateactivated protein kinase (AMPK) may couple hypoxic inhibition of mitochondrial oxidative phosphorylation to carotid body type I cell excitation (Evans, Mustard, Wyatt, Peers, Dipp, Kumar, Kinnear and Hardie 2005). Here we discuss evidence that AMPK is a key requirement for hypoxic chemotransduction by the carotid body. In addition, we postulate upon a role for AMPK in the plasticity observed in the carotid body during both chronic and chronic intermittent hypoxia.