An approach to software requirement specification using a structured bipartite inheritance network is presented. A bipartite inheritance network is a network with two different kinds of basic nodes, data entity and action, which are independent of each other and structured into an inheritance hierarchy. A structured bipartite inheritance network has a substructure, which is used primarily to decompose a large-scale software system into subsystems. This approach has the advantages that in software requirements specification both the data entities and functional components are explicitly specified such that it will be easier to identify and localize the requirement changes and are unified in a common structure so that the requirement specification will be easier to understand. A patient monitoring system is used to illustrate the specification procedure.