This chapter surveys soft errors induced by natural radiation on advanced complementary metal oxide semiconductor (CMOS) digital technologies. After introducing the radiation background at ground level (including terrestrial cosmic rays and telluric radiation sources), the chapter describes the main mechanisms of interaction between individual particles (neutrons and charged particles) and circuit materials; it also explains the different steps and production mechanisms of soft errors at device and cir- cuit levels. Then, soft error characterisation using accelerated and real-time tests is surveyed, as well as modelling and numerical simulation issues, with a special emphasis on the Monte Carlo simulation of the soft error rate (SER). Finally, the radiation response of the most advanced technologies is discussed on the basis of recently published studies focusing on deca-nanometre bulk, fully depleted silicon-on-insulator (FD-SOI) and FinFET families.