2026 ICD-10-CM Diagnosis Code J35.03Chronic tonsillitis and adenoiditis

ICD-10-CM Codes›J00–J99›J30-J39›J35

ICD-10-CM J35.03
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

J35.03 is a billable ICD-10-CM diagnosis code for chronic tonsillitis and adenoiditis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 152 through 153. Coders also document this condition as adenoiditis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute and chronic tonsillitis.

Code Identity

ICD-10-CM Code
J35.03
Billable Status
Yes — Valid for Submission
Code Describes
Chronic tonsillitis and adenoiditis
Short Description
Chronic tonsillitis and adenoiditis
Same as the full description in the CMS dataset.
Parent Code
J35.0
Chronic tonsillitis and adenoiditis

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ30-J39Other diseases of upper respiratory tract
CategoryJ35Chronic diseases of tonsils and adenoids
This CodeJ35.03Chronic tonsillitis and adenoiditis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adenoiditis
  • Chronic adenoid disease
  • Chronic adenoiditis
  • Chronic adenotonsillitis
  • Chronic disease of tonsil
  • Chronic disease of tonsils AND/OR adenoids
  • Chronic nasopharyngitis
  • Chronic tonsillitis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR RSP004
Acute and chronic tonsillitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Adenoids

Adenoids are a patch of tissue that is high up in the throat, just behind the nose. They, along with the tonsils, are part of the lymphatic system. The lymphatic system clears away infection and keeps body fluids in balance. The adenoids and tonsils work by trapping germs coming in through the mouth and nose.

The full article covers:

  • What are adenoids?
  • What are enlarged adenoids?
  • What causes enlarged adenoids?
  • What problems can enlarged adenoids cause?
  • How can enlarged adenoids be diagnosed?
  • What are the treatments for enlarged adenoids?
  • What is an adenoidectomy and why might I my child need one?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert J35.03 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
474.02 Chronic tonsils&adenoids
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About J35.03Overview

What is the ICD-10 code for chronic tonsillitis and adenoiditis?

The ICD-10-CM code for chronic tonsillitis and adenoiditis is J35.03 (sometimes written as J3503). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is J35.03 (Chronic tonsillitis and adenoiditis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report chronic tonsillitis and adenoiditis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does J35.03 group to?

When chronic tonsillitis and adenoiditis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 152, 153, with relative weights from 0.7382 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of J35.03?

Under the General Equivalence Mappings, chronic tonsillitis and adenoiditis converts to ICD-9-CM 474.02 (chronic tonsils&adenoids). The mapping is a direct match.