The FLUKA Monte Carlo code has been widely applied and benchmarked in recent years to problems related to Galactic Cosmic Rays (GCR) and Solar Energetic Particle (SEP) events. Applications range from fundamental cosmic ray and neutrino physics, to doses to commercial aircraft and space radiation issues in low orbit or in deep space. The main results of interest for fundamental physics concern the fluences of particle in atmosphere and a selection of results are reviewed. As far as applications are concerned, a review of calculations of relevance for aircraft crew dosimetry will be presented. Recently, the FLUKA database has been extended to include the spectra of the SEP events of October 28th 2003 and of January 20th 2005 for which detailed data exist for the light and heavy components. The GCR and SEP spectra have been used to compute absorbed doses, and dose equivalent for various organs as well as averaged over the whole body, for idealized spacecrafts and lunar shelters.