Insurance is a kind of protection against the damages that could happen, through the combination of the elements faced with the same risks. In the core of the concept of insurance lies the need to take some precautions in order to compensate for the damages that are likely to occur in the world with people living. The insurance sector has the function of intermediary in creating the funds necessary for the investments. Insurance firms keep the premiums they collect as a warrant for the demand of compensation for the future events. Some of the money is directed to capital markets and investors have the opportunity to invest in the funds created through insurance sector. This function of financial intermediary is especially important in closing the gap of investment in countries. Insurance sector is of great importance in the developing countries in terms of compensating for the risks in the fields of economy, industry, agriculture, export, transport and other fields. It is only possible to perform business activities in a secure manner through a well-established insurance sector and the existence of a sound insurance warranty in whatever field it is. As the insurance sector flourish, so do the types of insurance. Nearly everything in the present day can be insured within the frame of material values and responsibility. The old types of insurance have been substituted by more complex insurance groups.In our country, insurance activities are grouped under two main headings as life-related and non life-related. Besides, as of 27th October 2003, pension insurance became one of the branches with the outset of individual pension system. Insurance sector is an important fiscal and financial sector creating funds for the economy and inspiring security. As in all sectors, the understanding of efficient service delivery is of great significance. Efficiency is a kind of performance measurement determining the level of reach to the objectives set at the outset of the business. Hence, the concept efficiency is objective-oriented and determines the realization of the objectives by associating them with the output of the business. Insurance sector is a branch of service sector developing swiftly in the last few years. With the advances in technical fields, the existence of insurance firms depends on a variety of factors. These are low cost through rational use of resources, meeting the demands of the customers through promoting quality, and providing sufficient performance in managerial and technical tasks. Efficient use of performance measurements such as quality, cost, flexibility taking into account the fundamental elements such as change, competition, and examining the interaction among these have become one of the main fields of interest for the insurance firms. Performance is an umbrella term covering the dimensions of efficiency, effectiveness and quality, which makes it obligators for the unit to be measure from different aspects and in the measurement of performance efficiency and/or productivity methods should be used. One of the most commonly used methods in the evaluation of companies is “Efficiency Analysis”. Efficiency measurement helps the company to find its position in the competitive environment and shows how to use the inputs to produce optimum output. Turkish insurance sector has a dynamic structure after lifting the fee quotas on Accidents Insurance, Engineering Insurance and Agricultural Insurance and then Fire and Freight Insurance. Thanks to these developments, the insurance sector has a market in line with competitive and free market conditions. In these new markets, the efficient use of resources is very important and it is a must that the insurance firms should be assessed relatively for the performance in the sector and the reference companies should be determined to get their position in the efficiency border.The objective of this study is to evaluate the relative efficiency of the 25 insurance firms in non life-related field based on the 2005, 2006 and 2007 data. In order to perform the evaluation, a non-parametric method, Data Envelopment Analysis has been employed. Besides, in order for the inefficient insurance firms to guide, the rate input and output percentiles have been explained and at what percentile should the inefficient firms change in their input and output has been outlined. The results are expected to be useful for the insurance companies and researches in the field.