Tumours metastasizing to the heart are one of the least investigated subjects in clinical oncology. Nevertheless, this problem holds great practical significance in relation to the operability and type of treatment of neoplastic patients. Of 4769 patients autopsied at the Institute of Pathological Anatomy of Trieste from 1994 through 1995, 1148 males (42%) and 780 females (38%) had a primary tumour. Among them, 162 subjects had cardiac metastases (8.4%) of all cancers), with a significant decrease in frequency in elderly patients. Mesothelioma, melanoma and lung cancer showed the highest frequency of heart involvement in males (100, 50 and 31%, respectively). Melanoma, lung tumours and renal neoplasms had the highest percentages of secondary heart lesions in females (45, 26 and 20%, respectively). In lung cancer, anaplastic small-cell carcinoma (37%) and adenocarcinoma (33%) showed the most frequent heart involvement in males, while squamous carcinoma (43%) and anaplastic small-cell carcinoma (29%) had the highest frequency of heart metastases in females. Adenocarcinoma (82%) and anaplastic small-cell carcinoma (74%) of the lung, mesothelioma (100%) and breast tumours (73%) had the highest frequency of metastases to the pericardium. A particularly high frequency of myocardial involvement was observed in squamous cell carcinoma of the lung (62%), urinary tract tumours (60%) and melanoma (45%).