Over the last decade, 3D animation has undergone a huge expansion in quality and in its application. Today there are various kinds of softwares that can create very realistic 3D models and animations. The process of creating 3D animation consists of several stages (planning, designing, modeling, texturing, camera and lighting imposing, animation, rendering, compositing and so on) that are necessary for a successful production. Although omnipresent, 3D animation is still technically and economically very challenging, partly because of the knowledge and the time required for its implementation, but also because of the high prices of the softwares. The question this thesis shall answer is if free and open source software is capable of producing good quality content that may compete with other so-called closed source softwares. This paper has introduced the possibility to create a 3D animation in an open source program and has explored its features and benefits. In the process of making one it has been explained how to make a 3D CGI animation from scratch till the very end of production. Open source software is when the source code or design of the software itself is available to the general public for viewing, usage and further distribution. Software used for the purposes of this paper is called Blender. Each year, this software has been improved and upgraded, and users can even participate in its development. This thesis strives to explain how open source software works, to explore its capabilities and how they affect the future of animation. Also, in this paper, the basic rules, skills and work organisation required to complete a production of a 3D animation are explained and mastered.