The magnetic fields in our Galaxy, in the intergalactic space and around cosmic ray sources have significant effects on the observed arrival direction distribution, spectrum and composition of the ultra-high energy cosmic rays observed at Earth. I revisit some selected topics regarding the propagation in the regular Galactic magnetic field and in turbulent extragalactic magnetic fields. These include the formation of multiple images and the modification of large-scale anisotropies of extragalactic origin by the Galactic field. The arrival direction distribution and enhancement of the flux from a source in the presence of a turbulent field is also discussed, as well as the magnetic horizon effect that limits the flux of low-energy particles from a distribution of sources. The role of these effects in scenarios proposed to explain the spectrum, composition and anisotropies is highlighted.