Process validation is used to confirm that the resulting product from a specified process consistently conforms to product requirements. A risk-based approach to process validation provides a rational framework for developing an appropriate scope for validation activities, focusing on processes that have the greatest potential risk to product quality. This article presents a case study in which a risk-based approach was used to evaluate a typical mammalian cell culture and purification process. This risk assessment used a Failure Modes and Effects Analysis (FMEA) to evaluate the impact of potential failures and the likelihood of their occurrence for each unit operation. Unit operations included in the process validation required a risk priority number greater than or equal to a specified threshold value. Unit operations that fell below the threshold were evaluated for secondary criteria such as regulatory expectations or historical commitments.