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E66.01 — Morbid (severe) obesity due to excess calories
E66.01
What this code means
Morbid (severe) obesity due to excess calorie intake: a body mass index in the highest range with serious health risk.
Also called: morbid obesity, severe obesity.
When this code is used
Used for morbid (severe) obesity due to excess calories, alongside a BMI code.
Where it sits in ICD-10-CM
Code E66.01 belongs to Chapter 4: Endocrine, nutritional and metabolic diseases, which covers codes E00–E89 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.
Learn more about this condition
Watch: related videos
Frequently asked questions
What is ICD-10-CM code E66.01?
E66.01 is the ICD-10-CM diagnosis code for “Morbid (severe) obesity due to excess calories”. Morbid (severe) obesity due to excess calorie intake: a body mass index in the highest range with serious health risk.
When is code E66.01 used?
Used for morbid (severe) obesity due to excess calories, alongside a BMI code. It belongs to Chapter 4 of ICD-10-CM (Endocrine, nutritional and metabolic diseases).
This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.