2026 ICD-10-CM Diagnosis Code C66Malignant neoplasm of ureter

ICD-10-CM CodesC00–D49C64-C68C66

ICD-10-CM C66
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C66 is a non-billable ICD-10-CM category code for malignant neoplasm of ureter, so it cannot be submitted on claims. Use a more specific code from this category instead, such as C66.1, C66.2, and C66.9.

Code Identity

ICD-10-CM Code
C66
Billable Status
No — Non-Billable Category
Code Describes
Malignant neoplasm of ureter
Chapter
C64-C68
Malignant neoplasms of urinary tract

Code Classification

ChapterC00–D49Neoplasms
SectionC64-C68Malignant neoplasms of urinary tract
CategoryC66Malignant neoplasm of ureter
This CodeC66Malignant neoplasm of ureter

Specific Coding for Malignant neoplasm of ureterOverview

Non-specific codes like C66 require more characters. Use one of these billable codes instead:

  • Use C66.1 for Malignant neoplasm of right ureter

  • Use C66.2 for Malignant neoplasm of left ureter

  • Use C66.9 for Malignant neoplasm of unspecified ureter

Tabular List NotesGuidance

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

Type 1 Excludes

  • malignant neoplasm of ureteric orifice of bladder C67.6

Patient EducationClinical

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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 C66Overview

Is C66 (Malignant neoplasm of ureter) a billable code?

No. This is a category header that groups the codes for malignant neoplasm of ureter, and headers cannot be submitted on claims. Claims for malignant neoplasm of ureter need a more specific code from this category, such as C66.1, C66.2, and C66.9.