We have successfully fabricated nanocrystalline Co2MnSi Heusler alloy glass-coated microwires with a metallic nucleus diameter of 10.2 μm and total diameter 22.2 μm by the Taylor–Ulitovsky technique. Magnetic and structural investigations have been performed to clarify the basic magneto-structural properties of the Co2MnSi glass-coated microwires. XRD showed a well-defined crystalline structure with a lattice parameter a = 5.62 Å. Metallic nucleus of both annealed and as-prepared sample show L21 cubic ordered structured mixed with the amorphous glass coating. The hysteresis loops showed unique thermal stability with temperature, the coercivity (Hc) exhibits roughly stable temperature behavior. The annealed sample shows anomalous magnetic behavior with temperature at applied external magnetic field H = 5 kOe, where different four trends of magnetization curves with temperature are observed. The obtained results illustrate the sensitivity of Co2MnSi-based glass coated microwires to the temperature and magnetic field which make it a promising material for sensing application.