Within seventy years (1920-1989), Taiwan areais accomplishing the population transition and epidemiological transition in fastest speed than the Westem nations. Thisfastest transition in population and epidemiology causes the dramatic change in age structure. And, the aging population will be increasing faster in future forty to fifty years. Based on cohort component method used by this study, the result of the population projection demonstrates that the aged population occupies 6% (1,200,000) of total Taiwan population in 1989, the percentage will increase to 10% (2,420,000) in 2009, and over 20% (5,320,000) in 2034. Additionally, employing the multilogistic regression, the result shows tbat even if tbe advanced medical standard and living standard can delay the occurance of diseases to tbe final life stage of tbe elderly, the populaton of no self-care ability elder will still be increasing in fast speed. In 1989,the ppopulation of no self-care ability elder is 50,000. According to the methods of compression of morbidity (low projection) and failure of success (high projection), this no self-care ability elderly population will be 180,000 and 410,000 in 2034. In accordance with tbis huge aging population, based on tbis projection,in 1994, the necessary nursing professionals will be 2,405 (low projection) and 13,845 (high projection); 11,709(low) and 55,194 (high) in 2034. However, there are only 10 nursing professionals in 1989 and 30 health-care professionals in March, 1990 in Taiwan area. Thus, the imperative need in in-home nursing professionals and multi-health-care system are suggested by this study.