The topic of the thesis is the creation of an augmented reality android application for mobile devices in the Unity environment. The application is applicable for a children's encyclopedia about the animal world, where a specific animal is recognized by the camera of a mobile device through a marker and its virtual 3D model is displayed on the open page of the encyclopedia. The theoretical part explains the current development and applications of augmented reality. Furthermore, introduction of the 3D program for creating computer graphics Blender, the cross-platform environment for creating games Unity and the Vuforia tool intended for the development of augmented reality applications and games within Unity. The practical part describes the process of creating animated 3D animal models for the encyclopedia, their import from Blender into the Unity environment, the use of the Vuforia tool to create and place markers, and the adjustment of all other elements within the Unity environment. As a conclusion, the advantages and disadvantages of the existing technology of augmented reality by the way of projection using markers on the substrate and the future of graphic products in combination with augmented reality will be stated.