Malignant ovarian tumors have been continuously increasing in Western countries and represent the leading cause of death for gynecological cancer. In fact, the mortality for malignant ovarian tumors remains very high with a low percentage of 5-year survival in the advanced stage of disease. The aim of this study was to evaluate the incidence trend and epidemiological characteristics of malignant ovarian tumors in the Province of Sassari, Sardinia (Italy) in the period 1992-2001 and to report the variations in comparison to the 1974-1985 period. The analysis of our data regarding the period 1992-2001, if compared with those of the period 1974-85, showed an increase of malignant ovarian tumors which triplicated achieving an incidence of 11.99/100,000 vs 4.27/100,000. The analysis of our epidemiologic data showed an increase of the age of first diagnosis (mean 60.9 years for epithelial ovarian tumors), the occurrence of the cancer in women at low socio-economic levels and a family history of cancer among the patients with malignant ovarian tumors. These data suggest that both local environmental factors combined with genetic characteristics play a role in the pathogenesis of ovarian tumors. The genetic characteristics could be of particular interest because Sardinia has been through the centuries a geographical area with little population migration. The marked increase in the incidence of ovarian tumors in the last several years points out the need to organize systematic screening by ultrasonography in our population.