ICD-10 Code F51.3 – Sleepwalking [somnambulism] (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F51.3 – Sleepwalking [somnambulism]
What it is
F51.3 identifies sleepwalking, also called somnambulism. It describes episodes of walking or performing other behaviors during sleep, usually with reduced awareness and little or no memory afterward.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include partial arousal from sleep, automatic behaviors, confusion on awakening, and amnesia for the event.
When to use this code
Use this code when the record clearly documents sleepwalking as the reason for evaluation or as an established diagnosis. It may also fit when nocturnal ambulation or complex sleep behaviors are described as somnambulism. Confirm the provider has not documented another sleep disorder or seizure-related cause.
Do not use for
Do not use this code for ordinary insomnia, nightmares, or intentional nighttime activity. Check documentation if the behavior is better explained by seizures, medication effects, or another parasomnia.
Coding tip
Code F51.3 only when the provider explicitly links the behavior to sleepwalking; otherwise, query for clarification.