The article presents a review and summary on the development of studies in the field of axoplasmic transport in non-adrenergic and adrenergic neurons. Results obtained by, for example, histochemical, biochemical, electronmicroscopical, autoradiographical and radiological studies are discussed. Two main types of axoplasmic transport appear to operate in neurons; the slow axonal flow of 1 to 2 mm/day, and the fast transport exceeding 100 mm/day. However, also intermediary rates have been observed. The influence of nerve activity and drugs on axoplasmic transport is discussed, in relation to the possible mechanisms for axoplasmic transport which may operate in the neuron.