Process validation is a requirement of the Current Good Manufacturing Practices Regulations for Finished Pharmaceuticals, 21 CFR Parts 210 and 211, and of the Good Manufacturing Practice Regulations for Medical Devices, 21 CFR Part 820, and therefore, is applicable to the manufacture of pharmaceuticals and medical devices. Lyophilization is an essential component of synthesis and formulation processes in chemical and pharmaceutical industry. Therefore, it is needed to be validation and per regulatory requirements. Successful process validation programs begin with a thoughtful and comprehensive corporate policy concerning the process validation program. This policy should recognize that process validation begins at the initial stages of development, and does not end until the lifetime of the product is over. It is important that all employees be fully trained and understand their role in the program. Good science, well-documented development programs, proactive procedures and definitions, and well-written protocols will increase the chances of successful process validation.