The objective of the thesis is to analyzex-efficiency of Thailand's life insurance industry.X-efficiency is the motivation of the organizationmanagement. The research methods include descriptiveanalysis and regression analysis of x-efficiency index.Pooling data of 12 registered life insurers in theThailand from 1989-1994 are employed. The data aregathered from Insurance Department, Ministry ofCommerce. For ergression analysis, first, we estimate costfundtions for 12 life insurers to find out the cost oflife insurers associated with x-efficiency for eachyear. Second, we test the factors determiningx-efficiency. The research findings reveal that advertisingexpenses, market share and benifit payment ratiosignificantly determine and negatively x-efficiency oflife insurers. Non-admitted assets, investment assets,joint venture, commission ratio, equity ratio and law,however, insignificantly effect x-efficiency. Thereforethis study recommends that life insurers should screenfor higher quality policies and provide trainingcourses to personnel to have more knowledge forunderwriting. Government should closely supervise lifeinsurer to ensure stability of the system and promotebetter image of insurance industry.