We present a methodology to evaluate the sensitivity of pharmaceutical batch processes to scaling up. The Scale Up Risk Evaluation (SURE) is applied on new processes that are part way through their development. SURE combines the chemist’s process knowledge and the engineers knowledge of large-equipment functionality to come to a balanced, shared, long-term view of the risks to successful scale up. During a SURE study (i) the current process understanding is collated, then (ii) possible scenarios that pose a threat to the smooth operation of a process on a larger scale are identified and (iii) the likelihood of such a scenario being realised and the severity of its impact are scored. The final output of the SURE study is a ranked list of scenarios that development teams use to prioritise further development. The SURE process fosters collaboration between chemists and engineers, and helps engineers to define where their contributions to process development are of most value.