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Internal Medicine

Rebecca L. Warkol, MD

Works at hospitals in Greenwich, CT · Stamford, CT · Connecticut

Summary

Dr. Rebecca L. Warkol, MD is an internal medicine doctor at 8 W End Ave, Old Greenwich, CT 06870. Phone: (203) 637-5406. Accepts Medicare assignment. In 2024, Rebecca L. Warkol had 171 Original Medicare patients and 1,170 services. NPI 1184820110. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Internal medicine doctor (Medicare lists Internal Medicine)
  • Address: 8 W End Ave, Old Greenwich, CT 06870 · Directions
  • Phone: (203) 637‑5406
  • Medicare: Accepts Medicare assignment
  • Hospitals: Greenwich Hospital Association -, Stamford Hospital
  • Group practice: Old Greenwich Medical Group LLC (+1 more)
  • Medical school: New York Medical College · graduated 2003 (23 years since medical school)
  • Gender (as listed): Female
  • Telehealth: offered

From official Medicare data

This page shows what Medicare's official clinician data says about Rebecca L. Warkol, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Rebecca L. Warkol accept Medicare assignment?
Yes. Medicare's clinician data says Rebecca L. Warkol accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Rebecca L. Warkol see?
In 2024, CMS data shows 171 Original Medicare patients and 1,170 services for Rebecca L. Warkol. This counts Original Medicare only and measures volume, not quality.
What is Rebecca L. Warkol's NPI number?
1184820110. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Rebecca L. Warkol, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients171
Services billed to Medicare1,170
Different services or procedures22
Participating Medicare providerYes
Average age of these patients74

Most frequent services

  1. Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)276 services
  2. Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)198 services
  3. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)164 services
  4. Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report (93000)153 services
  5. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)127 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • High cholesterol75%
  • High blood pressure52%
  • Osteoporosis36%
  • Arthritis35%
  • Anxiety24%
  • Depression22%

Hospitals where Rebecca L. Warkol works

Medicare's Facility Affiliation Data lists Rebecca L. Warkol at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

  • Greenwich Hospital Association -Greenwich, CT · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 070018
  • Stamford HospitalStamford, CT · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 070006

Practice locations

Addresses where Rebecca L. Warkol is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Rebecca L. Warkol as a member of these groups (CMS data updated October 2, 2026).

  • Old Greenwich Medical Group LLC5 clinicians in the group
  • Rebecca Warkol MD LLC4 clinicians in the group

Specialties

Find other Internal Medicine doctors in Connecticut →

Other internal medicine doctors in Old Greenwich

Clinicians with the same Medicare primary specialty in Old Greenwich, CT — not a recommendation.

All internal medicine doctors in Old Greenwich →

Other clinicians in Old Greenwich Medical Group LLC

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolNew York Medical College
Graduation year2003 (23 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
TelehealthOffers telehealth services
NPI (National Provider Identifier)1184820110
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians