Thyroid dysfunctions have close relationship with cardiovascular diseases. As thyrotropin distribution shifts progressively toward higher levels with age, specific reference ranges for thyroid function tests should be established for the elderly. Recently, more and more attention is paid to subclinical thyroid diseases. Some evidence shows that subclinical hyperthyroidism exerts important effects on cardiac structure and functions, and it also increases the risk of atrial fibrillation. However, subclinical hypothyroidism might be a potential risk factor for heart failure, ischemic heart disease and all-cause mortality, although it is still controversial. Cardiovascular disease associated with hyper- and hypothyroidism will be improved when thyroid function returns to normal. Since physiologically decreased thyroid activity to some extent might have favorable effects in the very old patients, more clinical evidence should be provided to illuminate the effects of subclinical thyroid dysfunction on cardiovascular diseases; and large, randomized clinical trials are needed to identify the target populations of individuals with subclinical thyroid dysfunction who will be benefited after thyroid treatment.