Cardiac metastases from bronchogenic carcinoma are not commonly diagnosed prior to death. This study isolates factors associated wtih the development of cardiac involvement. Four hundred eighteen consecutive patients with lung cancer who had autopsies were studied. Twenty-five percent of these patients had cardiac involvement. Factors associated with cardiac metastases were (1) histologic cell type of the tumor, (2) aggressive therapy, (3) extent of disease, and (4) tumor differentiation. The presence of cardiac metatases was not related to the length of survival. Clinical signs of cardiac involvement included an enlarging heart on the chest x-ray film, development of congestive heart failure, or electrocardiographic changes. Suspicion of cardiac metastases in high-risk individuals, prompt diagnostic evaluation, and rapid institution of therapy may improve the outlook for many patients, since reaccumulation of fluid was generally slow.