CTA, the Cherenkov Telescope Array, is the next generation ground-based observatory for gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. The sensitivity in the core energy range will be dominated by up to 40 Medium- Sized Telescopes. These telescopes, of Davies-Cotton type with a reflector with a diameter of 12 m, are currently in the prototype phase. A full-size mechanical prototype with drive system has been constructed in Berlin. Different prototype mirrors have been developed, tested and are mounted on the prototype. Two camera types are designed and prototyped. Demonstrator cameras were built and are tested; the integration of these cameras on the prototype is prepared. A report on all aspects of the design, commissioning and performance of the Medium-Sized Telescopes and their main components will be given.