Implementation of so-called Early Warning Systems (EWS) had grown exponentially from its birth in the mid-twentieth century. That growth has been in number, sophistication and application realms (earthquakes, floods, global warming, hurricanes...). This paper analyses the use of Early Warning Systems in the contemporary logics of biosurveillance. In order to do this, we will offer an analysis of documentary material and images, both pertaining to the study case focused on epidemics and biosecurity we conducted for three years. The aim is to illustrate the features of the contemporary biosurveillance logics. Finally, we will conclude by saying that in these logics of biosurveillance are brewing a profound change in the way life is monitored. We have called it biomonitorization: life is no longer just passive and controlled by different devices; now, it also plays an active, surveilling and monitorizing role. Then, citizens become biocitizens.