Most recent studies are based on benchmarking analysis allowing the measure of company efficiency relatively to a reference performance. Benchmarking is a helpful tool to analyze and promote efficiency in insurance companies. The fast development of X-efficiency notion makes traditional performance measures (ROA, ROE, etc.) obsolete. Indeed, various methods have been used, various input-output measures have been proposed and various research fields have been explored in insurance company investigation. So, after reviewing most known efficiency concepts and their definitions, this section explores the literature review of two principal points of discussion: the first point is focused on the different used techniques to measure efficiency, including the developed approaches to define inputs, outputs and their prices. The second point represents an overview of efficiency investigations in insurance industry.