Recently, virtual manufacturing has emerged as an important concept in the development of manufacturing systems. To implement a virtual manufacturing system, it is necessary to construct digital models for all physical and logical elements of the real manufacturing system. In this research, an efficient and systematic methodology for creating an object-oriented virtual manufacturing system model is proposed. The proposed approach for developing a virtual manufacturing system includes four stages: (1) functional analysis, (2) behavior analysis, (3) virtual system model construction and (4) virtual system implementation. IDEF0 and object-oriented petri net (OPN) are integrated into the corresponding stages based on their characteristics. In addition, the concept of a virtual device is proposed as a reference model for constructing the virtual manufacturing system model. In order to develop the system rapidly and efficiently, transformation rules between the IDEF0 and OPN and between the OPN and the virtual device are constructed. Finally, an assembly and packaging system is produced to illustrate the proposed approach for developing a virtual manufacturing system model.