Mammalian cell biotechnology has expanded in recent years from a technology principally concerned with vaccine production to one that now also includes monoclonal antibodies and drugs for cardiovascular, respiratory and immune diseases. Development of commercial cell culture processes for the production of these biological products is performed at bench and pilot-scale prior to commercial implementation. Successful scale-up from bench-scale to manufacturing-scale is dependent on process and product comparability across the scales and the availability of robust qualified models. Effective technical support for investigations and process improvements also relies on the availability of these qualified bench- and pilot-scale models. The performance of bench-scale, pilot-scale and commercial-scale bioreactors for the production of a fusion protein and a monoclonal antibody was characterised in this work.