The proliferation of the wireless network over the last decade is one of the significant drivers for the increased deployment of mobile ad hoc networks (MANETs) in the battle field. It is not practically possible to build a fixed wired network infrastructure in battle field. But it is possible to create a mobile wireless network infrastructure because of the mobility of the soldiers. MANET is justified by the possibility of building a network where no infrastructure exists. MANET with group communication applications and multicasting can highly benefit from a networking environment such as military and emergency uses. In such applications, the used ad hoc networks need to be reliable and secure. In recent years, a specific technique called the universal generating function technique (UGFT) has been applied to determine the network reliability. The UGFT is based on an approach that is closely connected to generating functions that are widely used in probability theory. This work devotes to assess the MANET reliability using the UGFT. Reliability of the MANET is defined as the probability that the transformed message from the source can be passed successfully through the MANET and reached the target without any delay. Two kinds of UGFs are discussed in this work, and an algorithm has been proposed to execute the system reliability. This UGFT is illustrated with a case study in a battlefield environment. An MC consists of transmitting a packet to a group of mobile nodes identified by a single destination MC address and hence is intended for a group-oriented computing. The multicast service is employed in areas of a collaborative work, for example, in rescue operations, battlefields, video conferencing, and so on. An MC packet is typically delivered to all members of its destination group with the same reliability as regular unicast packets. An MC can reduce communication costs and the delivery delay. In addition, it can provide a robust communication mechanism when the receiver's individual address is changeable.Network reliability is an important part of planning, designing, and controlling network. There are many approaches for executing network reliability. 1-3 Chaturvedi and Misra 4 have proposed a hybrid method to evaluate the reliability of complex networks. Ahmad and Omid 5 have calculated the all terminal network reliability using recursive truncation algorithm. Some authors 6-9 have evaluated