WiMAX is a wireless digital communication system based on the IEEE 802.16 standard which provides broadband wireless Internet access at very high rates that is up to 70 Mbps or a data rate of about 3 Mbps within a radius of 30-mile (data rate increases as the distance decreases). With the rapid increase in the wireless broadband use, the need for wireless fixed and mobile metropolitan area networks has ever been increasing. Multimedia communications, including audio and video are highly bandwidth demanding and error sensitive. When the coverage area of the wireless network technology is as high as with WiMAX, security becomes one of the most important issues.WiMAX, both mobile and fixed, has many attractive features such as connection-oriented MAC layer, provision of the Quality-of-Service (QoS) for different applications, efficient mobility and power save mode features. Needless to say, all these attractive features must be protected against malicious activities by security mechanisms.Providing secure multimedia communications by using a broadband wireless technology like WiMAXis likely to be challenging due to time or space overhead that occur. Security mechanisms might increase packet sizes thus delay, jitter and throughput are increased. In this paper, we evaluate the performance of secure video transmission over WiMAX networks under different cryptographic algorithms by using the OPNET simulator. The outcome of the results show negligible overhead introduced by the security extensions giving credence to their application in security sensitive scenarios.