To establish whether an echocardiogram is always necessary when investigating heart failure (HF) in elderly patients. a clinical assessment was compared with echocardiography in 51 elderly patients aged ≥75 years complaining of breathlessness of more than 1 month's duration. the greater the number of clinical features of HF present, the more likely was echocardiography to reveal a potential cause. It revealed a potential cause of HF in all 16 patients with strong clinical evidence (four or more features present). Of the 20 patients in whom clinical evidence of HF was equivocal (two or three features present), the echocardiogram revealed a potential cause of HF in nine and so was valuable in directing the diagnosis towards or away from HF. In only two of the 15 patients with minimal clinical evidence of HF (one feature or less) did the echocardiogram reveal a potential cause of HF. Severe valvular lesions were common, occurring in 20 (39%) patients. These were difficult to identify clinically as clinical features were non-specific and murmurs were not always present. echocardiography is most useful in those elderly patients in whom the clinical diagnosis of HF is uncertain or for whom valvular surgery might be considered.