Among the various types of materials with thermoelastic martensitic transformations and shape memory TiNi-based alloys have the highest strength and plastic properties. They also exhibit unique shape-memory effects (SME) and reproducibility (single-way and reversible, or two-way, SME, hyperelasticity, damping, ets), as well as high reliability and good mechanothermal, mechanocyclic, thermocyclic lifetimes. In addition, they exhibit weldability, corrosion resistance, and biocompatibility; have a relatively simple chemical composition and are characterized by a good workability of the metallurgical process and subsequent industrial procedures. As alloys with a SME, they are irreplaceable in critical articles and state-of-the-art devices in medicine. In this paper the main classes of medical TiNi -based alloys and, accordingly, types of medical application of given materials as instruments and implants are considered. The novel modern methods and new approaches for improvement of structure and properties of TiNi shape- memory alloys have been discussed.