From medical imaging to particle physics passing, among others, by space applications, integrated readout electronics (ICs) in CMOS technologies are often adopted. When a high sensitivity and a low noise level are required, cooling of detectors and readout electronics is the recommended solution. To maintain a constant cooling temperature, they very often operate at nitrogen and helium-4 liquids temperatures, respectively 77 K and 4.2 K. At these temperatures, Spice parameters of MOSFET transistors may be found in the literature. However, their performances at sub-kelvin temperatures remain unknown because of a lack in scientific publications thereupon. CEA Astrophysics division's focal plane arrays-based bolometers are cooled at 0.1 K. The front-end electronics also. However, a CMOS technology was characterized for the first time at sub-kelvin temperatures. It is shown by measured n and p channel transistors' I-V that the AMS 0.35 μm standard bulk CMOS technology, is still performing at 0.1 K. Despite some specific effects on silicon behaviour at cryogenic temperatures, performances are very satisfactory.