2026 ICD-10-CM Diagnosis Code G40Epilepsy and recurrent seizures

ICD-10-CM Codes›G00–G99›G40-G47›G40

ICD-10-CM G40
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G40 is a non-billable ICD-10-CM category code for epilepsy and recurrent seizures, so it cannot be submitted on claims. Use a more specific code from this category instead, such as G40.001, G40.009, G40.011, and G40.019.

Code Identity

ICD-10-CM Code
G40
Billable Status
No — Non-Billable Category
Code Describes
Epilepsy and recurrent seizures
Chapter
G40-G47
Episodic and paroxysmal disorders

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG40Epilepsy and recurrent seizures
This CodeG40Epilepsy and recurrent seizures

Specific Coding for Epilepsy and recurrent seizuresOverview

Non-specific codes like G40 require more characters. Use one of these billable codes instead:

  • G40.0 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset

  • G40.00 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable

  • G40.01 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable

  • G40.1 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures

  • G40.10 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable

  • G40.11 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable

  • G40.2 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures

  • G40.20 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable

  • G40.21 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable

  • G40.3 for Generalized idiopathic epilepsy and epileptic syndromes

  • G40.30 for Generalized idiopathic epilepsy and epileptic syndromes, not intractable

  • G40.31 for Generalized idiopathic epilepsy and epileptic syndromes, intractable

  • G40.4 for Other generalized epilepsy and epileptic syndromes

  • G40.40 for Other generalized epilepsy and epileptic syndromes, not intractable

  • G40.41 for Other generalized epilepsy and epileptic syndromes, intractable

  • Use G40.42 for Cyclin-Dependent Kinase-Like 5 Deficiency Disorder

  • G40.5 for Epileptic seizures related to external causes

  • G40.50 for Epileptic seizures related to external causes, not intractable

  • G40.8 for Other epilepsy and recurrent seizures

  • G40.80 for Other epilepsy

  • G40.81 for Lennox-Gastaut syndrome

  • G40.82 for Epileptic spasms

  • G40.83 for Dravet syndrome

  • G40.84 for KCNQ2-related epilepsy

  • Use G40.89 for Other seizures

  • G40.9 for Epilepsy, unspecified

  • G40.90 for Epilepsy, unspecified, not intractable

  • G40.91 for Epilepsy, unspecified, intractable

  • G40.A for Absence epileptic syndrome

  • G40.A0 for Absence epileptic syndrome, not intractable

  • G40.A1 for Absence epileptic syndrome, intractable

  • G40.B for Juvenile myoclonic epilepsy [impulsive petit mal]

  • G40.B0 for Juvenile myoclonic epilepsy, not intractable

  • G40.B1 for Juvenile myoclonic epilepsy, intractable

  • G40.C for Lafora progressive myoclonus epilepsy

  • G40.C0 for Lafora progressive myoclonus epilepsy, not intractable

  • G40.C1 for Lafora progressive myoclonus epilepsy, intractable

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • conversion disorder with seizures F44.5
  • convulsions NOS R56.9
  • post traumatic seizures R56.1
  • seizure convulsive NOS R56.9
  • seizure of newborn P90

Type 2 Excludes

  • the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled

Patient EducationClinical

Epilepsy

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About G40Overview

Is G40 (Epilepsy and recurrent seizures) a billable code?

No. This is a category header that groups the codes for epilepsy and recurrent seizures, and headers cannot be submitted on claims. Claims for epilepsy and recurrent seizures need a more specific code from this category, such as G40.001, G40.009, and G40.011.