Dramatic changes in fertility and mortality rates during the 20th century ensured that the world  would age rapidly during the 21st century. The number of elderly is now increasing by 8 million per year; by 2030, this increase is expected to reach 24 million per year. Levels of illness and disability among the elderly group far exceed those for other age groups, and that is the reason why  the needs of this group are likely to increase substantially in the 21st century. Chronic diseases exact a particularly heavy health and economic burden on older adults due to associated long-term illness, diminished quality of life, and greatly increased health care costs. Although the risk of disease and disability clearly increases with advancing age, poor health is not an inevitable consequence of aging. Much of the illness, disability, and death associated with chronic disease is avoidable through known prevention measures and critical knowledge gaps exist for responding to the health needs of older adults. The clinically important consequences of geriatric patients due to diminished physiological reserve are; disease presentation in older persons are often atypical, usually there is the context of contributing comorbid conditions, the compensatory mechanism is weakened, recover from ilness is slow, certain preventive measures are beneficial and the weekened reserve puts the elderly at greater risk for iatrogenic injury. The well-being of older persons often depends on the realization of the recommendations based on the scientific  researches. Although considerable progress has been made in understanding the multiple problems in elderly, there are still some  gaps. Particularly in need of the multidisciplinary approach not only in the scientific research area, but in the services as well.