This review examines the possible role of neurotransmitters present in the carotid body on the functional expression of chemosensory activity during postnatal development. In particular, dopamine, acetylcholine, adenosine and neuropeptides are reviewed. Evidence to date shows involvement of these transmitters in signal transmission from the chemoreceptor cells to chemosensory afferent fibers of the sinus nerve, with clear age- or maturation-dependence of some aspects. However, it remains unresolved whether these neurotransmitters, some of which are expressed in the carotid body before birth, are directly involved in the maturation of the functional properties of the carotid chemoreceptors in sensing oxygen or other stimuli during postnatal development.