ICD-10-CM 2027
ICD-10 code for obesity
Confirmed by the official ICD-10-CM index entry “obesity”. Page updated September 29, 2026.
About coding obesity
The ICD-10-CM code for obesity is E66.9 (Obesity, unspecified). The official index lists 9 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on E66.9.
It is also searched as morbid obesity.
Within E66, choose E66.9 (Obesity, unspecified) only when documentation doesn't support a more specific option: obesity due to excess calories (E66.0), drug-induced obesity (E66.1), Morbid (severe) obesity with alveolar hypoventilation (E66.2), Overweight (E66.3) and other obesity (E66.8).
Code first: obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-).
Use an additional code to identify body mass index (BMI), if known, for adults (Z68.1-Z68.45) or pediatrics (Z68.5-).
Related Obesity codes
- E66.01 Morbid (severe) obesity due to excess calories
- E66.09 Other obesity due to excess calories
- E66.1 Drug-induced obesity
- E66.2 Morbid (severe) obesity with alveolar hypoventilation
- E66.3 Overweight
- E66.811 Obesity, class 1
- E66.812 Obesity, class 2
- E66.813 Obesity, class 3
- E66.89 Other obesity not elsewhere classified
Common questions about obesity ICD-10 codes
What is the ICD-10 code for obesity?
- E66.9 — Obesity, unspecified. More specific codes apply when the documentation supports them: E66.01, E66.09, E66.1, E66.2 and others below.
What is the ICD-10 code for morbid (severe) obesity due to excess calories?
- E66.01 — Morbid (severe) obesity due to excess calories.
What is the ICD-10 code for other obesity due to excess calories?
- E66.09 — Other obesity due to excess calories.
What is the ICD-10 code for drug-induced obesity?
- E66.1 — Drug-induced obesity.
What is the ICD-10 code for morbid (severe) obesity with alveolar hypoventilation?
- E66.2 — Morbid (severe) obesity with alveolar hypoventilation.
What is the ICD-10 code for overweight?
- E66.3 — Overweight.
What is the ICD-10 code for obesity, class 1?
- E66.811 — Obesity, class 1.
Is E66.9 billable?
- Yes. E66.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E66.9 be used as a principal diagnosis?
- It can, but When it is the principal diagnosis, Medicare considers it a questionable reason for an inpatient admission, so claims may be reviewed.
Is E66.9 a CC or MCC?
- No. E66.9 is neither a CC nor an MCC under MS-DRG v44.0.