The International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) is based on the World Health Organization's Ninth Revision, International Classification of Diseases 2012 (ICD-9). ICD-9-CM is the official system of assigning codes to diagnoses and procedures associated with hospital utilization in many countries. The ICD-9 is used to code and classify mortality data from death certificates.

The ICD-9-CM 2012 consists of a tabular list containing a numerical list of the disease code numbers in tabular form, an alphabetical index to the disease entries; and a classification system for surgical, diagnostic, and therapeutic procedures.

The ICD has been in use since its inception in 1900. It is updated annually with minor revisions and every three years with major revisions, and it is republished in a fully revised version every ten years. It has been published by the WHO since 1970. The United States Department of Health and Human Services publishes their own further indexed version of the ICD to include diagnostic and operative procedures, which at present is ICD-9-CM, meaning clinically modified. In addition to statistics and mortality rates, the ICD is used for health records, reimbursement systems, and public data.