The neuropeptide somatostatin is involved in many functions in the central nervous system as well as in the periphery. When it is centrally injected, an irreversible apnea is often developed. In the present review, we discuss the effects of somatostatin as the result of its actions at three levels of the respiratory neural network: a) by modulating the output of cranial or spinal motoneurons; b) by altering the genesis of the respiratory rhythm in the brainstem; and c) by regulating the chemosensory drive input into the respiratory pattern generator