Unique amongst visceral organs, the gastrointestinal tract contains an own intrinsic nervous system. This so-called enteric nervous system (ENS) is the largest and most complex part of the peripheral nervous system and provides the gut autonomous control of peristalsis, blood flow and secretion. An even broader functional significance of the ENS is being recognised through its communication with the brain, immune system and microbiota. ENS dysfunction has been associated with many disorders including Hirschsprung disease, achalasia and Parkinson's disease. Despite the essential role of ENS in gut physiology and disease, the variety of functionally distinct neurons and how they specify during development has not been resolved. By applying single cell transcriptome analysis we have recently established a new classification of enteric neuron subtypes and a mechanistic mode for how these neuron identities emerge. The molecular definition of enteric neuron classes give us a foundation to reveal their detailed developmental programs and precise functions both within and outside the gut.