Mathematical modeling of mechatronic systems is increasing in its importance to industry for product development. Mathematical modeling helps companies reduce the lead time for new product development, allows for consideration of more design alternatives, provides a means for capture of engineering knowledge, and facilitates sharing of engineering efforts with suppliers. Structured modeling further assists engineers in meeting these goals by supporting effective, clear communication of model information. This paper describes a modeling environment for mechatronic system design based on structured modeling concepts. Structured modeling is implemented using a multiport template approach. A multiport template allows the engineer to create new user-defined model types, which are in turn used to create computational instances. The focus is on mechatronic component modeling. Illustrations of the method are given.