Information systems have to respond well to the changing business environment. Thus, they must have architecture which withstands the change. To design such systems, business process modeling is effective, however, the models include often abstractness and arbitrariness. Therefore, there have been efforts that validate rigorousness of the models. They have defined semantics of the models and applied various logics and formal methods to verification of the rigorousness. This paper focuses on formal verification of the models and surveys the efforts. We also discuss the prospect of the solutions. The establishment of the verification will be surely helpful toward solving the problems on business process reengineering, business process management, service-oriented architecture, and so on.