Alkyl ketene dimer (AKD) is a common sizing agent, which is suitable for any kind of cellulose and its derivatives. To control of the penetration of liquids from paper surface is important by terms of printability and protecting the products from liquids. AKD sizing applications are becoming increasingly important in parallel with technologic development of industrial applications. It is necessary to examine the present state of the paper industry and the traditional practices in order to successful sizing. Pulp and paper industry, still major practitioner of the AKD, has the proper experience about AKD production and application. Besides that, there is growing interest about AKD applications certain area of engineering. This review is a brief outline showing experiments on AKD from researchers.