Most of the basic research on the electrical behavi or of CNTs has been carried out on individual or bundle nanotubes. More recently random or oriented CNT networks (CNTN) are emerging as new material for electronic application. We present the fabrication of thick and dense CNTNs, in the form of freestanding films, and the study of their electric resistance as a functio n of the temperature, from -200 to +150 °C. A non-metallic behavior has been observed with a monotonic R(T). A good long-term stability and a behavioral accordanc e with the temperature measured Si or Pt thermistor are demonstrated. We underline that a transition from n onmetallic to metallic can take place at few degrees below 0°C. A model involving regions of highly anisotropi c metallic conduction separated by tunneling barrier regions can explain the non-metallic to metallic crossover, based on the competing mechanisms of the metallic resista nce rise and the barrier resistance lowering.