The sensitization of AISI 304 stainless steels at low temperature has been studied. A heat treatment for 15 min between 650 and 850 degree C is sufficient to provoke a strong sensitization of steels when heated for 24 hours at 500 degree C. Short treatments at temperatures over the limits of the TTS (Temperature-Tensile Strength) curve favor the sensitization of steels at temperatures between 400 degree C and 500 degree C. The low temperature sensitization is shown to cause precipitation of chromium carbide particles making stainless steels susceptible to intergranular corrosion.