Guillermo Marrero, M.D.
NPI 1245211044 · Internal Medicine Physician · Oviedo, FL
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Guillermo Marrero, M.D. is a Internal Medicine Physician provider in Oviedo, FL (NPI 1245211044).
Provider details
- NPI number
- 1245211044
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- ME0074991 (FL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
20 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
755 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. 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 .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 434 | $88 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 153 | $120 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 99 | $125 |
| Injection of Drug Or Substance Under Skin Or Into Muscle96372 | 69 | $14 |
Typical Medicare-allowed amounts for these services range $14–$125 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 97 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Rosuvastatin Calcium | 285 | 96 |
| Levothyroxine Sodium | 197 | 62 |
| Amlodipine Besylate | 193 | 64 |
| Atorvastatin Calcium | 165 | 51 |
| Losartan Potassium | 103 | 30 |
| Carvedilol | 99 | 28 |
| Lisinopril |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$385 across 17 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2005-11-09
- Last updated
- 2010-09-22
Frequently asked questions
- What is Guillermo Marrero's NPI number?
- Guillermo Marrero's National Provider Identifier (NPI) is 1245211044, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Guillermo Marrero's specialty?
- Guillermo Marrero is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Guillermo Marrero located?
- Guillermo Marrero's practice location on file with NPPES is 1000 Executive Dr, Oviedo, FL 32765-8140.
- What is Guillermo Marrero's phone number?
- The practice phone number listed in the NPPES registry for Guillermo Marrero is (407) 971-1970.
- Does Guillermo Marrero accept Medicare?
- Guillermo Marrero is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Guillermo Marrero's NPI active?
- Yes — Guillermo Marrero's NPI (1245211044) is active in the NPPES registry as of the last update on 2010-09-22.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.