As the whole territory of Armenia is situated in very high seismoactive zone seismic risk assessment of dams is very important for Armenia. The problem of anthropogenic seismicity related with operation of reservoirs is essential in geophysics and earthquake engineering, especially for the reservoirs, which are constructed in seismically active regions. We have collected and analyzed the data on the current reservoir's and dam's situation and then pointed out the main factors that determine the risk's levels. Our investigations, performed for the three most dangerous homeland large dams, are based on the main principles of total risk analysis for dams, presented in the recommendations of International Committee of Large Dams (ICOLD [1-3]). In this paper it has been also shown, that the number of microearthquakes increase after reservoir operation, causing changes of seismic regime in observed regions.