Guillermo Diaz, NP-P
NPI 1164975801 · Psychiatric/Mental Health Nurse Practitioner · Hicksville, NY
Enrolled with Medicare as Practitioner - Nurse Practitioner · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Guillermo Diaz, NP-P is a Psychiatric/Mental Health Nurse Practitioner provider in Hicksville, NY (NPI 1164975801).
Provider details
- NPI number
- 1164975801
- Entity type
- Individual
- Primary specialty
- Psychiatric/Mental Health Nurse PractitionerPhysician Assistants & Advanced Practice Nursing Providers
- Credential
- NP-P
- Sex
- Male
- Sole proprietor
- No
- License
- 402068 (NY)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
9 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
2 documented practice locations
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 9 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Quetiapine Fumarate | 58 | 23 |
| Alprazolam | 22 | — |
| Sertraline Hcl | 22 | 12 |
| Citalopram Hydrobromidebrand: Citalopram Hbr | 17 | — |
| Duloxetine Hcl | 14 | — |
| Mirtazapine | 14 | — |
| Aripiprazole |
Practice location
Mailing address
Additional practice locations (1)
- 1985 Marcus Ave Ste 110New Hyde Park, NY 11042-2024Phone: (855) 201-4988
Registry dates
- Enumerated
- 2016-07-29
- Last updated
- 2025-09-05
- Certified
- 2025-09-05
Frequently asked questions
- What is Guillermo Diaz's NPI number?
- Guillermo Diaz's National Provider Identifier (NPI) is 1164975801, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Guillermo Diaz's specialty?
- Guillermo Diaz is listed in the NPPES registry with a primary specialty of Psychiatric/Mental Health Nurse Practitioner (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Guillermo Diaz located?
- Guillermo Diaz's practice location on file with NPPES is 185 W John St # 113, Hicksville, NY 11801-1007.
- What is Guillermo Diaz's phone number?
- The practice phone number listed in the NPPES registry for Guillermo Diaz is (646) 856-9971.
- Does Guillermo Diaz accept Medicare?
- Guillermo Diaz is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Guillermo Diaz's NPI active?
- Yes — Guillermo Diaz's NPI (1164975801) is active in the NPPES registry as of the last update on 2025-09-05.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.