Sarcoptic mange is the most severe infection in chamois in the Eastern Alps. This study analyses and discusses data from two mange foci in the Foresta Demaniale di Tarvisio (NE Italy). The first impact of mange on naive host populations was dramatic, with mortality rates of over 80%. The chamois herds were decimated, but they recovered quite fast and two later epizootics were observed to have a far less severe impact on the chamois population. Intervals between successive waves lasted 10 to 15 years. No sign of low reproductive performance nor evidence of a poor physical condition of the animals was observed in the years preceding the new epizootic waves. Mortality rates were only slightly influenced by the density of the host population. In a long lasting focus of disease, adult males appeared more vulnerable to mange than other sex and age classes. Cases of mange were also more frequent in winter and spring. This seasonal trend may be explained by the interaction between the dynamics of mites, ethological patterns-rut activity-and the poorer physical condition of the host during this period.