The frequency and severity of clinical and subclinical heart damage were studied in patients who had been treated with adriamycin (ADR) as part of the Cooperative Osteosarcoma Studies (COSS). The study charts of 785 patients from 63 participating institutions were reviewed: The overall incidence of drug-induced congestive heart failure was 2.2% (17 cases, 5 fatal). Late left ventricular function was studied in 29 tumor free survivors 81 +/- 41 month after treatment with 342 +/- 113 mg/m2 ADR. A detailed history and physical exam for signs of overt heart disease were obtained. M-mode echocardiography (ECHO, 29 cases) with evaluation of the fractional shortening rate (FS) and radionuclide ventriculography (RNV, 18 cases) with determination of the systolic ejection fraction at rest (EF) were used to screen for subclinical cardiac disease. Impaired cardiac function leading to pathological values was documented in close to one half of these patients. The frequency and severity of clinical and subclinical heart damage increased with cumulative adriamycin and time since cessation of anthracycline therapy.