Diabetes affects 10~25% of elderly people older than 65 years of age worldwide. Various factors contribute to age-related glucose intolerance. Perhaps the most important factor is the impairment of insulin-mediated glucose disposal, especially in skeletal muscles, which is particularly the case in obese subjects. The number of insulin receptors and their binding capacity are not consistently affected by age. Contributory factors may include increased body fat mass, physical inactivity and diabetogenic drugs such as thiazide. The ability of insulin to enhance blood flow is also considerably reduced in obese, insulin-resistant diabetic subjects. In elderly diabetic patients with advanced microvascular complications(especially diabetic nephropathy and retinopathy), the likelihood of ameliorating their progression may be small. Therefore, more conservative therapeutic targets (e.g., fasting glucose < 140mg/dl and a postprandial glucose<200~220 mg/dl) may be more prudent. The other major endocrinological conditions encountered in the elderly are apathetic thyrotoxicosis and unsuspected hypothyroidism. Screening for thyroid disease is an essential element in routine check-up in the elderly. Thyroid hormone replacement has to be slow to avoid aggravation of coexisting heart problems. The serum free calcium does not change with age, however, PTH has been shown to increase with age in both men and women and has been implicated as a factor for bone loss in the elderly. Several age-related changes can account for the rise in PTH. The incidence of primary hyperparathyroidism is increasing in the elderly, and in most cases, the patients are asymptomatic at the time of diagnosis. The lean body tissue mass steadily declines after the age of 20, whereas the level of body fat increases and reaches a peak at around 60. One can imagine an older person with a "normal" BMI but with increased intra-abdominal fat. Obesity is not as common in elderly people as in younger adults, possibly because obesity is associated with a higher mortality in the young. Excessive weight is more incapacitating in elderly people than in the young because of the general decrease in the muscle mass and the additional pathology associated with aging.