The aim of this paper was to present the process of training, recognizing and replacing faces using deep learning tools, which represent the most modern approach in the field of artificial intelligence and neural networks in learning and defining faces, and point out potential real threats of using such technology. sides. The paper consists of a theoretical and a practical part. In the theoretical part, the terms machine learning and deep learning and key elements and differences are defined. The structure and mode of operation of the neural network are presented, as well as the basic principles of operation used for deep learning. The emphasis of the paper is on the applications of deep learning and the techniques used by various applications in which deep learning for facial recognition is implemented are presented. In the practical part of the paper, research was conducted using facial recognition tools. The computer program FaceSwap applies the principle of deep learning to create "deep fakes" in which the algorithm learns the main features of the face and replaces the original faces in pictures or videos with the desired face of another person. After showing the system and analyzing the mode, the practical part of the face replacement in the video is shown and finally the results are shown. The last chapter deals with ethical principles and points out the dangers and possible abuse and protection against inappropriate use.