This work presents an extensive analysis of the analog properties, in particular in terms of noise performance, of MOSFET devices belonging to a 65 nm low power CMOS technology exposed to ionizing radiation. The behavior of the 1/f and white noise terms is studied as a function of the main device parameters before and after exposure to 10 keV X-rays and 60Co γ-rays. The results provide a valuable tool to understand the mechanisms underlying performance degradation in nanoscale CMOS technologies. They also provide criteria for the design of high-density, rad-hard analog front-end circuits.