Cardiac function was evaluated by noninvasive methods in 55 patients with stage II or III breast cancer treated with adjuvant Adriamycin containing combination chemotherapy (FAC). None of the 44 patients who remained free of disease for a median follow-up period of 36 months, or those who were retreated with Adriamycin up to a median cumulative total dose of 450 mg/m2 (nine patients), developed clinical evidence of cardiac decompensation. The median electrocardiographic QRS voltage and ejection fraction decreased by 11% and 5%, respectively, in the former and by 21% and 10% in the latter group at the conclusion of chemotherapy. These parameters tended to return to the baseline at the time of the last visit. The decreases in QRS voltage and ejection fraction were greater in patients who received radiotherapy and had prior cardiovascular disease than in those without such risks. The remaining two patients were retreated with higher total doses of Adriamycin. Both showed clinical evidence of cardiac decompensation and gradual deterioration of the noninvasively measured parameters of cardiac function. One patient was alive six months after the discontinuation of Adriamycin at a total dose of 842 mg/m2, and the other died of pulmonary embolism two months after receiving a total of 892 mg/m2. Our study shows that Adriamycin can be included in adjuvant therapy without inducing clinically significant alterations in cardiac function; however, patients who have additional risk factors should be monitored closely with noninvasive studies while they receive this drug.