Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Internal Medicine

Johanna Martinez, MD

Works at hospitals in Manhasset, NY · New York

Summary

Dr. Johanna Martinez, MD is an internal medicine doctor at 865 Northern Blvd, Great Neck, NY 11021. Phone: (516) 622-5070. Accepts Medicare assignment. In 2024, Johanna Martinez had 20 Original Medicare patients and 65 services. NPI 1821210865. 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: 865 Northern Blvd, Great Neck, NY 11021 · Directions
  • Phone: (516) 622‑5070
  • Medicare: Accepts Medicare assignment
  • Hospital: North Shore University Hospital
  • Group practice: North Shore-Lij Medical PC
  • Medical school: State University Of New York At Stony Brook, School Of Medicine · graduated 2004 (22 years since medical school)
  • Gender (as listed): Female

From official Medicare data

This page shows what Medicare's official clinician data says about Johanna Martinez, 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 Johanna Martinez accept Medicare assignment?
Yes. Medicare's clinician data says Johanna Martinez 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 Johanna Martinez see?
In 2024, CMS data shows 20 Original Medicare patients and 65 services for Johanna Martinez. This counts Original Medicare only and measures volume, not quality.
What is Johanna Martinez's NPI number?
1821210865. 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 Johanna Martinez, 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 patients20
Services billed to Medicare65
Different services or procedures13
Participating Medicare providerYes
Average age of these patients75

Most frequent services

  1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)33 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 blood pressure70%
  • High cholesterol65%

Hospitals where Johanna Martinez works

Medicare's Facility Affiliation Data lists Johanna Martinez 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.

  • North Shore University HospitalManhasset, NY · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 330106

Practice locations

Addresses where Johanna Martinez is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Johanna Martinez as a member of this group (CMS data updated October 2, 2026).

  • North Shore-Lij Medical PC6,440 clinicians in the group

Specialties

Find other Internal Medicine doctors in New York →

Other internal medicine doctors in Great Neck

Clinicians with the same Medicare primary specialty in Great Neck, NY — not a recommendation.

All internal medicine doctors in Great Neck →

Other clinicians in North Shore-Lij Medical PC

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

Clinician information

CredentialMD
Medical schoolState University Of New York At Stony Brook, School Of Medicine
Graduation year2004 (22 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1821210865
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