Skip to content
Dx

ICD-10-CM 2027 diagnosis code

G20Parkinson's disease

Not billable — use a more specific code

G20 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.

Code last changed in FY2024 (effective October 1, 2023). Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G20

G20 is the ICD-10-CM diagnosis code for Parkinson's disease. It belongs to block G20-G26 (extrapyramidal and movement disorders) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: G20.A (without dyskinesia), G20.B (with dyskinesia) and G20.C (unspecified).

Use an additional code, if applicable, to identify: dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4), dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-), dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3), dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2), dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0) and 1 more.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2024 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as 332.0 (paralysis agitans).

Specific codes under G20

Coding notes

Applicable toConditions and synonyms classified to this code
  • Hemiparkinsonism
  • Idiopathic Parkinsonism or Parkinson's disease
  • Paralysis agitans
  • Primary Parkinsonism or Parkinson's disease
Use additional codeAdd a secondary code to fully describe the condition

Notes that apply from higher levels

Instructions written at a parent level also apply to G20.

Broader instructions also apply from Chapter 6: Diseases of the nervous system.

Codes whose notes reference G20

ICD-9-CM equivalent

Converter →
  • 332.0Paralysis agitansapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • FY2024 (effective 10/1/2023): Expanded — no longer billable

Common questions about G20

Is G20 billable?

No. G20 is a header code. Report one of its more specific subcodes instead.

What is the ICD-9 code for G20?

The CMS General Equivalence Mappings map G20 to ICD-9-CM 332.0.