Validation or verification of manufacturing processes and associated test methods are a significant aspect of manufacture of therapeutic goods. Guidance and methodology to be used to achieve the desired validation or verification outcomes are included in regulatory guidelines, Codes of GMP, pharmacopoeias and international standards. However, such studies are not always performed properly. Three cases will be discussed where inadequate validations of microbiological quality/efficacy tests applied to therapeutic goods led to challenging outcomes for both the product manufacturers and the TGA .