Quality characteristics must be assured through adherence to good manufacturing practices in the production, control, and testing of drug products intended for investigational as well as commercial use. A draft guideline on the preparation of investigational new drug products, soon to be available in final form, addresses questions that have been raised regarding acceptable practices and procedures to facilitate compliance with the CGMP regulations as applied to clinical supplies. Inspections of sterile clinical supplies production can be expected to include the areas most likely to influence product safety, quality, and uniformity in the same manner as would be expected regarding the manufacture of commercial batches. Some areas of particular significance in the manufacture of parenteral clinical supplies include validation of terminal sterilization, aseptic processing, and oxygen exclusion. The validation of the aseptic handling during lyophilization requires special attention. Other CGMP concerns include the provision of a quality control unit, avoiding packaging mixups, and being prepared for an amendment to the CGMP regulations regarding terminal sterilization.