The International Classification of Diseases (ICD), developed by the World Health Organization, aims to provide a uniform language for healthcare documentation. The U.S. transition from ICD-9 to the more detailed ICD-10 is mandated for all HIPAA-covered entities by October 1, 2015, emphasizing the need for training, operational changes, and proper coding to ensure reimbursement. Successful implementation involves careful planning, communication, assessment, and adequate training for all staff to adapt to the complexities of the new coding system.