Liver cirrhosis is considered as a double etiology disease, being its incidence and mortality associated either to alcohol consumption or to a previous viral hepatitis infection of type "B" or "neither A nor B". A two components mathematical model is here used to estimate the proportion of liver cirrhosis mortality attributable to alcohol consumption and the proportion from hepatitis. The model has been fitted to mortality data of the 95 Italian provinces in 5 periods of three years each from 1969 to 1983. In 1981-83, the first-component (interpretable as due to alcohol) is estimated to account for 31% in males and 28% in females of total mortality from liver cirrhosis. Estimates are given also for large geographical areas, regions and provinces.