Drugs are critical elements in health care. They must be manufactured to the highest quality levels. End-product testing by itself does not guarantee the quality of the product. Quality assurance techniques must be used. In the pharmaceutical industry, process validation performs this task, ensuring that the process does what it purports to do. It is also a regulatory requirement. This paper presents an introduction and general overview of this process, with special reference to the requirements stipulated by the US Food and Drug Administration (FDA).