Abstract"Risk assessment" is a relatively new concept in Argentina, since the very first hazard map was only recently constructed on the basis of the 1992 eruption of Copahue volcano (Patagonia). Copahue is considered a very active volcanic system since 13 eruptive events have been recognized over the last 260 years. Most the events are phreatic and phreato-magmatic with VEI ≤ 2; nevertheless such eruptions represent a threat for the communities living in the surrounding areas of the emission centre, not only because of pyroclastic flows and tephra fall (the nearby villages, Caviahue and Copahue, have so far only experienced ash fallout), but also due to the possible formation of mud flows and flank collapse triggered by the volcanic activity. Owing to the frequent eruptions of Copahue, the most recent ones (2000, 2012) showed an increasing explosive character, hazard survey actions, such as thematic maps and contingency plans are constantly, though slowly, modified. The risk assessment described in this chapter calls for the implementation of the monitoring network in the Argentina side of the volcano, since the only currently active seismic stations (OVDAS) are located in the Chilean side of the volcanic edifice, Copahue volcano lying at the border between the two countries. Moreover, the Chilean observatory adopts criteria of alert levels, which