Résumé
The transport of galactic cosmic rays from the sources to the Earth in the interstellar medium is an essential process for the understanding of several observations: abundances of secondary nuclei produced by spallation reactions, abundances of radioactive elements, diffuse multi-wavelength backgrounds, the lepton cosmic ray spectrum. The transport of cosmic ray in the interstellar medium is controlled by their interactions with magnetic turbulent fluctuations. The review addresses recent analytical and numerical developments in the modeling of the microphysics of magnetic turbulence and charged particle interactions in the interstellar medium. Issues on the cosmic ray escape from the sources is also considered. Finally, the transport of low energy cosmic rays is commented in the view of the problems related to the ionization of interstellar matter.