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GUSTAVO H DAY MD PA
NPI 1659559664
Internal Medicine in Dallas, TX

Active since February 01, 2008
7777 FOREST LN, BUILDING B, SUITE 416, DALLAS, TX 75230(972) 566-6764(972) 566-6968 Get Directions Write a Review

NPPES record last updated: May 18, 2026. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: May 18, 2026, Apr 12, 2024 (2 updates tracked since 2024).

About Gustavo H Day Md Pa NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

GUSTAVO H DAY MD PA (NPI 1659559664) is a healthcare organization registered as an internal medicine in Dallas, Texas and active in the NPI registry since February 2008. The organization lists Gustavo Horacio Day, Owner, as its authorized official.

NPPES Registry Identity

NPI1659559664
Entity TypeOrganization
Primary Taxonomy207R00000X
Legal Business NameGUSTAVO H DAY MD PA
Location Address7777 FOREST LN, BUILDING B, SUITE 416Dallas, TX 75230-2505
Mailing AddressPo Box 738305Dallas, TX 75373-8305 · (972) 566-6764 · Fax (972) 566-6968
Phone(972) 566-6764
Fax(972) 566-6968
Organization SubpartNo
Authorized OfficialGustavo Horacio DayOwner · (972) 566-6764
Enumeration DateFebruary 1, 2008
Last NPPES UpdateMay 18, 20262 updates tracked since enumeration
NPPES CertifiedMay 18, 2026
✔ NPI 1659559664 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
7777 FOREST LN, Dallas, TX 75230
Open in Google Maps ↗

Other Identifiers 1

MedicaidP00040AM6TX

Group Practice 1

Group TaxonomyThis provdier is a business group of one or more individual practitioners, all of who practice with the same area of specialization.193400000X SINGLE SPECIALTY GROUP

Accepted Insurance

The full list of accepted plans is on the Insurance tab. Issuers include Molina Healthcare.Insurance ›

Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Gustavo H Day Md Pa is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

2

Medicare enrollment records show 2 clinicians reassign Medicare billing to Gustavo H Day MD PA, which bills Medicare for the services they deliver. Of these, 2 practice at this address. They are listed nearest first.

Clinicians, nearest first (2)

Gustavo Day, M.D.
Internal Medicine
NPI 1538239173
7777 FOREST LN BUILDING B, SUITE416
Dallas, TX 75230
(972) 566-6764
✔ PECOSSame address
Melissa Garcia, FNP-C
Nurse Practitioner
NPI 1609487222
7777 FOREST LN STE 416
Dallas, TX 75230
(972) 566-6764
✔ PECOS✔ Accepts MedicareSame address

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

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 Gustavo H Day MD PA's NPI number?

The NPI number for Gustavo H Day MD PA is 1659559664. It was assigned to this organization in the NPPES registry on February 1, 2008.

Where is Gustavo H Day MD PA located?

Gustavo H Day MD PA is located at 7777 Forest Ln Building B, Suite 416, Dallas, TX 75230. The listed phone number is (972) 566-6764.

What is Gustavo H Day MD PA's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Gustavo H Day MD PA enrolled in Medicare?

Yes. Gustavo H Day MD PA is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Gustavo H Day MD PA?

According to the CMS Revalidation Reassignment List (October 2026 release), 2 clinicians reassign their Medicare billing to Gustavo H Day MD PA, in Internal Medicine and Nurse Practitioner. A 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 the clinician's services. Of these, 2 practice at this address. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

What insurance does Gustavo H Day MD PA accept?

Health plans from Molina Healthcare list Gustavo H Day MD PA 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 Gustavo H Day MD PA was last updated on May 18, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 months 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.