2026 ICD-10-CM Official Guidelines for Coding and ReportingFY 2026
The complete Official Guidelines for Coding and Reporting, section by section, with linked codes, searchable rules, and every change from last year highlighted. A faster, fully cross-linked alternative to the CMS PDF.
Conventions & General Guidelines
Conventions for the ICD-10-CM
The conventions, general guidelines and chapter-specific guidelines are applicable to all health care settings unless otherwise indicated. The convent…
General Coding Guidelines
To select a code in the classification that corresponds to a diagnosis or reason for visit documented in a medical record, first locate the term in th…
Diagnosis Selection & Reporting
Selection of Principal Diagnosis
The circumstances of inpatient admission always govern the selection of principal diagnosis. The principal diagnosis is defined in the Uniform Hospita…
Reporting Additional Diagnoses
GENERAL RULES FOR OTHER (ADDITIONAL) DIAGNOSESFor reporting purposes, the definition for “other diagnoses” is interpreted as additional clinically sig…
Diagnostic Coding and Reporting Guidelines for Outpatient Services
These coding guidelines for outpatient diagnoses have been approved for use by hospitals/ providers in coding and reporting hospital-based outpatient …
What changed in FY2026
Sources and methodology
The guideline text on these pages is the official ICD-10-CM Official Guidelines for Coding and Reporting for fiscal year 2026, published word for word. CMS and the National Center for Health Statistics update these rules every year, and following them is required under HIPAA when you assign ICD-10-CM codes.
Each October we load the new release from CMS, keep the exact wording and the original outline numbers (for example, I.C.1.a), and flag what changed from the year before. Then we add what a PDF can't do. Related rules link to each other, every code gets a detail card, and the whole text is searchable. The wording of the rules doesn't change.
- ICD-10 at CMSThe official U.S. home for the ICD-10-CM and ICD-10-PCS code sets and the coding guidelines. This is the release we import each year.
- ICD-10-CM at NCHSThe National Center for Health Statistics, part of the CDC, maintains the diagnosis codes and puts out the guideline updates with CMS.
These pages match the CMS fiscal year 2026 release, effective October 1, 2025 through September 30, 2026. ICD List is independent. We aren't affiliated with CMS, the NCHS, or the World Health Organization.
