Recently, multimedia security is becoming more important with the continuous increase of digital communications on the internet. Moreover, special and reliable security is needed in many digital applications (such as video conferencing and medical imaging systems). The classical techniques for data security are not appropriate for the current multimedia usage. As a result, we need to develop new security protocols or adapt the available security protocols to be applicable for securing the multimedia applications. Encryption of MPEG-4 video streaming using AES has not been studied. In this paper, the performance of AES in encrypting MPEG-4 video is considered. The performance of AES is compared to two symmetric encryption techniques namely; RC4 and XOR. Three data types (text, audio and video) are used to test the effectiveness of AES in encrypting MPEG-4 . Simulations showed the efficiency of the AES encryption technique in such application for the different data type given.