Due to the prolonged life expectancy, the number of frail elderly or very old adults has increased. The health care needs of the elderly population are enormous. Nurses need to have sufficient gerontological nursing care knowledge and skills to make sound judgments about clinical problems, identify pathological aging process, provide better quality of care, and achieve cost-effective outcomes. The impact of physiological aging process is influenced by chemical, physical environment, diseases, life style, and genetics. The factors influencing the mental health of elders include physical health status, social relationship, and stress from life events. The most commonly reported mental health problems include anxiety, sadness, depression, and suicide. Through an understanding of normal aging changes in physical and mental health aspects, nurses would be able to conduct a thorough assessment, provide individual care, promote quality of care, and enhance quality of life for the elderly.