GUILLERMO DIAZ NP-P
NPI 1164975801
Nurse Practitioner - Psychiatric/Mental Health in Hicksville, NY
About Guillermo Diaz Np-p NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
GUILLERMO DIAZ NP-P (NPI 1164975801) is an individual psychiatric/mental health provider in Hicksville, New York, licensed in New York (402068) and active in the NPI registry since July 2016. He is enrolled in Medicare PECOS, maintains 3 additional practice locations, and is a graduate of Other (2016).
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Locations 3
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Guillermo Diaz Np-p is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show Guillermo Diaz reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Toms River, NJ 08753
- Reassigned Medicare billing, New York enrollment
- 62 clinicians in this Medicare group
Miami, FL 33130
- Reassigned Medicare billing, Colorado, Connecticut and New York enrollments
- 504 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 11801 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
HICKSVILLE, NY 11801
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Guillermo Diaz's NPI number?
The NPI number for Guillermo Diaz is 1164975801. It was assigned to this individual provider in the NPPES registry on July 29, 2016.
Where is Guillermo Diaz located?
Guillermo Diaz practices at 185 W John St # 113, Hicksville, NY 11801. The listed phone number is (646) 856-9971.
What is Guillermo Diaz's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Psychiatric/Mental Health, with taxonomy code 363LP0808X.
Is Guillermo Diaz enrolled in Medicare?
Yes. Guillermo Diaz is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Guillermo Diaz's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Guillermo Diaz reassigns Medicare benefits to 2 organizations: Wagner Medical PC (Toms River, NJ) and Grow Healthcare Group PA (Miami, FL). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Guillermo Diaz's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Guillermo Diaz accept?
Health plans from Anthem Blue Cross and Blue Shield list Guillermo Diaz as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
When was this NPI record last updated?
The NPPES record for Guillermo Diaz was last updated on October 12, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 19 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Guillermo Diaz, NP-P · NPI 1164975801
Psychiatric/Mental Health physician in Hicksville, New York. Individual provider, active in the CMS NPPES registry since July 29, 2016.
## Identity
- **NPI:** 1164975801 (Entity type: Individual)
- **Enumerated:** July 29, 2016
- **Primary specialty:** Nurse Practitioner - Psychiatric/Mental Health · taxonomy 363LP0808X
- **State license:** 402068 (New York)
- **Sole proprietor:** No
## Practice location
- **Address:** 185 W JOHN ST # 113, Hicksville, NY 11801-1007
- **Phone:** (646) 856-9971 · **Fax:** (516) 531-8539
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): Wagner Medical PC (NPI 1235951187, Toms River, NJ); Grow Healthcare Group PA (NPI 1245845932, Miami, FL) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2016
## Record status
- **NPPES last updated:** October 12, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1164975801) · Data from the CMS NPPES public registry.