ICD-10-CM 2027
ICD-10 code for severe obesity
From the official ICD-10-CM alphabetic index entry “Obesity › severe”. Page updated September 29, 2026.
About coding severe obesity
The ICD-10-CM code for severe obesity is E66.01 (Morbid (severe) obesity due to excess calories).
Within E66.0 (obesity due to excess calories), E66.01 is specifically for Morbid (severe) obesity due to excess calories. Related codes cover other obesity due to excess calories (E66.09).
Don't report E66.01 together with the conditions in its Excludes1 note: morbid (severe) obesity with alveolar hypoventilation (E66.2).
Code first: obesity complicating pregnancy, childbirth and the puerperium, if applicable (O99.21-).
Don't confuse with (Excludes1 for E66.01)
- morbid (severe) obesity with alveolar hypoventilation (E66.2)
Common questions about severe obesity ICD-10 codes
What is the ICD-10 code for severe obesity?
- E66.01 — Morbid (severe) obesity due to excess calories.
Is E66.01 billable?
- Yes. E66.01 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E66.01 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E66.01 as a principal diagnosis.
Is E66.01 a CC or MCC?
- No. E66.01 is neither a CC nor an MCC under MS-DRG v44.0.