Chronic instability is a frequent complaint in elderly patients. As literature on the subject is scarce, we investigated reversible causes, evaluating patients over 65 years of age referred to a regional neurological practice for disequilibrium lasting longer than three months. Clinical features were analyzed. Computerized tomography (CT) of the brain, and thyroid hormone and cyanocobalamin (Cc) serum levels were studied for all patients, as was clinical course. No CT abnormalities were found. Low Cc levels were observed in 6 patients, and 2 were diagnosed of previously undetected hypothyroidism. During the mean follow-up period of 12 months, improvement was seen in 3 specifically-treated patients, one with hypothyroidism and two with Cc deficit. We conclude that chronic instability in the older patient cannot usually be traced to a specific cause, but that it is important to protocolize the assessment of such patients, including routine tests for thyroid hormone and Cc levels, in order to rule out treatable causes.