ICD-10-CM 2027
ICD-10 code for parkinsonism
From the official ICD-10-CM alphabetic index entry “Parkinsonism (idiopathic) (primary)”. Page updated September 29, 2026.
About coding parkinsonism
The ICD-10-CM code for parkinsonism is G20.C (Parkinsonism, unspecified). The official index lists 20 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on G20.C.
Within G20, choose G20.C (Parkinsonism, unspecified) only when documentation doesn't support a more specific option: without dyskinesia (G20.A) and with dyskinesia (G20.B).
Don't report G20.C together with the conditions in its Excludes1 note: Parkinson's disease NOS (G20.A1), Parkinson's disease with dyskinesia (G20.B-), Parkinson's disease without dyskinesia (G20.A-) and secondary parkinsonism (G21.-).
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.
More specific parkinsonism codes (official index)
- with neurogenic orthostatic hypotension (symptomatic) G90.3 — Multi-system degeneration of the autonomic nervous system
- arteriosclerotic G21.4 — Vascular parkinsonism
- dementia G20.C — Parkinsonism, unspecified
- with behavioral disturbance G20.C — Parkinsonism, unspecified
- due to
- drugs NEC G21.19 — Other drug induced secondary parkinsonism
- neuroleptic G21.11 — Neuroleptic induced parkinsonism
- Parkinson's disease
- medication-induced NEC G21.19 — Other drug induced secondary parkinsonism
- neuroleptic induced G21.11 — Neuroleptic induced parkinsonism
- postencephalitic G21.3 — Postencephalitic parkinsonism
- secondary G21.9 — Secondary parkinsonism, unspecified
- due to
- arteriosclerosis G21.4 — Vascular parkinsonism
- drugs NEC G21.19 — Other drug induced secondary parkinsonism
- neuroleptic G21.11 — Neuroleptic induced parkinsonism
- encephalitis G21.3 — Postencephalitic parkinsonism
- external agents NEC G21.2 — Secondary parkinsonism due to other external agents
- syphilis A52.19 — Other symptomatic neurosyphilis
- specified NEC G21.8 — Other secondary parkinsonism
- syphilitic A52.19 — Other symptomatic neurosyphilis
- treatment-induced NEC G21.19 — Other drug induced secondary parkinsonism
- vascular G21.4 — Vascular parkinsonism
Don't confuse with (Excludes1 for G20.C)
Common questions about parkinsonism ICD-10 codes
What is the ICD-10 code for parkinsonism?
- G20.C — Parkinsonism, unspecified. More specific codes apply when the documentation supports them: G90.3, G21.4, G20.C, G20.C and others below.
What is the ICD-10 code for arteriosclerotic parkinsonism?
- G21.4 — Vascular parkinsonism.
What is the ICD-10 code for dementia parkinsonism?
- G20.C — Parkinsonism, unspecified.
What is the ICD-10 code for medication-induced nec parkinsonism?
- G21.19 — Other drug induced secondary parkinsonism.
What is the ICD-10 code for neuroleptic induced parkinsonism?
- G21.11 — Neuroleptic induced parkinsonism.
What is the ICD-10 code for postencephalitic parkinsonism?
- G21.3 — Postencephalitic parkinsonism.
What is the ICD-10 code for secondary parkinsonism?
- G21.9 — Secondary parkinsonism, unspecified.
Is G20.C billable?
- Yes. G20.C is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G20.C be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G20.C as a principal diagnosis.
Is G20.C a CC or MCC?
- No. G20.C is neither a CC nor an MCC under MS-DRG v44.0.