2026 ICD-10-CM Diagnosis Code J35.1Hypertrophy of tonsils

ICD-10-CM CodesJ00–J99J30-J39J35

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

J35.1 is a billable ICD-10-CM diagnosis code for hypertrophy of tonsils. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 154 through 156. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute and chronic tonsillitis.

Code Identity

ICD-10-CM Code
J35.1
Billable Status
Yes — Valid for Submission
Code Describes
Hypertrophy of tonsils
Short Description
Hypertrophy of tonsils
Same as the full description in the CMS dataset.
Parent Code
Chronic diseases of tonsils and adenoids

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ30-J39Other diseases of upper respiratory tract
CategoryJ35Chronic diseases of tonsils and adenoids
This CodeJ35.1Hypertrophy of tonsils

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Enlarged tonsil
  • Enlargement of left tonsil
  • Enlargement of right tonsil
  • Finding of size of tonsil
  • Hyperplasia of tonsils
  • Hypertrophy of tonsils
  • Large tonsils

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Enlargement of tonsils

Type 1 Excludes

  • hypertrophy of tonsils with tonsillitis J35.0

Index to Diseases and InjuriesGuidance

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Enlargement, enlarged
      • tonsils
    • Hyperplasia, hyperplastic
      • tonsils (faucial) (infective) (lingual) (lymphoid)
    • Hypertrophy, hypertrophic
      • lingual tonsil (infective)
    • Hypertrophy, hypertrophic
      • tonsils (faucial) (infective) (lingual) (lymphoid)

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

Convert J35.1 to ICD-9-CMHistory

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

ICD-9-CM
474.11 Hypertrophy tonsils
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 J35.1Overview

Is J35.1 (Chronic diseases of tonsils and adenoids) a billable code?

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

What MS-DRG does J35.1 group to?

When hypertrophy of tonsils is the principal diagnosis on an inpatient stay, it groups to MS-DRG 154, 155, 156, with relative weights from 0.6911 to 1.5635 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of J35.1?

Under the General Equivalence Mappings, hypertrophy of tonsils converts to ICD-9-CM 474.11 (hypertrophy tonsils). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.