Left ventricular (LV) and right ventricular (RV) function were evaluated at rest and during exercise using radionuclide ventriculography in 10 patients, aged 19-53 years, with sickle-cell anemia (SCA). Seven patients were in New York Heart Association functional class I and 3 were in class II. The resting LV ejection fraction (EF) was normal in 9 patients and the resting RVEF was normal in 4. LV dilation and high cardiac output were observed in 6 patients at rest. The LVEF during exercise was normal in all 10 patients, whereas only 2 patients had normal RVEF at rest and during exercise. The LVEF was lower in patients with SCA at rest (54 ± 4 % versus 61 ± 6%, p < 0.001) and exercise (66 ± 4% versus 74 ± 6%, p < 0.001) than in 42 age-matched normal subjects. Rest thallium-201 images from 9 patients showed abnormal RV uptake in 8 and normal LV uptake in 8. Thus, in adult patients with SCA, LV function was normal during exercise in all patients and at rest in all but 1 patient. The LVEF, however, was lower than that in age-matched normal subjects. RV function was abnormal in most patients at rest and during exercise. RV thallium-201 uptake suggested pressure or volume overload (or both), most likely due to pulmonary vaso-occlusive complications of the disease. © 1983.