CellML is an XML-based file format for describing mathematical models, with the aim of simplifying the creation, exchange and reuse of models. There are a number of software tools for modelling biological processes that can read and write CellML files. In this paper, we describe the ability of the OpenCell modelling environment to export CellML files to a number of different programming languages. We give an example of how OpenCell can be used together with MATLAB, a popular language for mathematical modelling, in cardiac cellular electrophysiology. Limitations and areas for future improvement in code export from OpenCell are also addressed.