The International Classification of Diseases 10th Revision Procedure Classification System (ICD-10-PCS) has been developed as a replacement for Volume 3 of the International Classification of Diseases 9th Revision. The development of ICD-10-PCS was funded by the U.S. Health Care Financing Administration. ICD-10-PCS has a multi-axial seven character alphanumerical code structure, which provides a unique code for all substantially different procedures and which allows new procedures to be easily incorporated as new codes. ICD-10-PCS was under development for over five years and the initial draft was formally tested and evaluated by an independent contractor. The final version of the ICD-10-PCS was released in the spring of 1998. The design, development and testing of ICD-10-PCS are discussed.