Hadrontherapy is an advanced technique of cancer radiation therapy which instead of X-rays employs beams of charged hadrons, protons and carbon ions in particular. Due to their physical and radio-biological properties, they allow to obtain a highly conformal treatment, sparing at best the surrounding healthy tissues. From being practised only in nuclear and particle physics laboratories, hadrontherapy is becoming today a clinical reality. By now about 45 ′ 000 patients have been treated worldwide with proton beams and several hospital based centres are either running or under construction. Carbon ions are characterized by a larger biological effectiveness than X-rays and protons and they are particularly suited to treat radio-resistant tumours. Carbon ion therapy is developing in the world and two hospital based centers are under construction in Europe. A large diffusion of hadrontherapy is foreseen in the near future but a much larger diffusion, possibly comparable with conventional X-ray radiation therapy, will be achieved only if much compact and cheap accelerators and dose delivery systems will be conceived and constructed. In this paper the present status of hadrontherapy and some innovative ideas for the future are summarized.