Ambulatory monitoring and health care using wireless body area networks is an active area of applied research. In this study, a new method is presented to compute the connectance and reliability of wireless body area networks based on an improved approach to the topological analysis of the network's digraph using Mason's rule. The procedure outlined is simple and fast and may be used to compute quantitative measures of a wireless body area network's reliability. [Life Science Journal 2010; 7(2): 52-56]. (ISSN: 1097-8135).