The data resulting from an epidemiological and anatomopathological study on ovarian tumours in the Trieste province are presented. 970 cases of ovarian neoplasms diagnosed in the Institute of Pathological Anatomy and Histology of Trieste University over the 1969-1985 period were analyzed: 66.7% were benign and 33.3% were malignant. The crude incidence of benign ovarian tumours was 24.2/100,000 and that of malignant tumours was 12.1/100,000. The incidence rate of the latter standardized on the world population was 6.5/100,000. It is a low level, which does not increase over time. Benign ovarian tumours affect all age groups, while malignant tumours are more frequent among elderly women. In addition, the distribution by age group varies according to the histological type. Among benign tumours, the most frequent are the epithelial ones (over 50% of the total), followed by tumours of germinal origin (27.5%), tumours of the ovarian stroma (21.6%) and those of ovarian non-specific tissues (0.8%). Among malignant neoplasms, epithelial ones are 94.4%, germinal tumours 2.8%, stromal tumours 1.8% and sarcomas 0.9%.