ICD-10-CM 2027
ICD-10 code for Mpox
From the official ICD-10-CM alphabetic index entry “Mpox”. Page updated September 29, 2026.
About coding Mpox
The ICD-10-CM code for Mpox is B04 (Monkeypox).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 865 (Viral Illness with MCC, relative weight 1.3485) and DRG 866 (Viral Illness without MCC, relative weight 0.8692), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Common questions about Mpox ICD-10 codes
What is the ICD-10 code for Mpox?
- B04 — Monkeypox.
Is B04 billable?
- Yes. B04 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B04 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B04 as a principal diagnosis.
Is B04 a CC or MCC?
- B04 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.