In their review recently published in Nature Reviews Neuroscience, Oxana Garritsen, Eljo van Battum, Laurens Grossouw and Jeroen Pasterkamp provide a comprehensive overview of the different molecular subsets and heterogeneity of dopaminergic neurons in the ventral midbrain of mice and humans. The authors first compare the currently defined subsets and then address molecular mechanisms that generate this diversity and that regulate subset positioning and target innervation in embryonic and early postnatal development. In addition, axonal wiring mechanisms and biological functions of dopaminergic neuron subtypes are extensively discussed. To further understand and treat diseases related to dopaminergic neurons, such as Parkinson disease, this review highlights the necessity of obtaining more extensive knowledge on midbrain dopamine neuron heterogeneity.