In this report Mr Jean-Pierre Door, Deputy, and Mrs Marie-Christine Blandin, Senator, study the ‘epidemic risk’. Diseases caused by an infectious agent today form the most complex public health problem, as the nature of the viruses, bacteria or prions which we may have to deal with is not known in advance. The public authorities are making a considerable effort in this field. The progress accomplished by the French health monitoring and alert system is remarkable, even if the 2003 heat wave showed there could be shortcomings in this system, which are analysed by the rapporteurs. One conclusion stands out: the policy combating the epidemic risk has to be all inclusive. It cannot be limited to medical issues. Hygiene, living conditions, and the level of information and culture are also fundamental parameters.