Cassandra Marie O'Connor, MD
Internal Medicine Physician · Roslyn, NY
Cassandra Marie O'Connor, MD is an internal medicine physician with a practice address in Roslyn, New York, and NPI 1184200289, issued on Mar 20, 2021. Check the license (New York 33108401, as entered in NPPES) on the NYS Education Department, Office of the Professions; the Medicare figures below come from public CMS files.
- Name
- Cassandra Marie O'Connor
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 33108401 NY
Self-reported in NPPES; status is on the state search - Practice location
- 100 Port Washington Blvd, Roslyn, NY 11576
- Phone
- (516) 562-6000
- Enumerated
- Mar 20, 2021
- Record last updated
- Aug 8, 2024
- Medicare enrollment
- Enrolled (PECOS I20240730002188); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 12,067 in New York → Look up another NPI →
Also registered at 100 Port Washington Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Zaid Ahmad, M.D.Anesthesiology Physician1871507947
Verify Cassandra Marie O'Connor in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersNYS Education Department, Office of the Professions
Search for license 33108401Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
89% fewer Medicare Part D claims than the average internal medicine physician in 2024
352 Medicare Part D claims for 128 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Furosemide22 claims
- Metoprolol Succinate18 claims
- Atorvastatin Calcium16 claims
- Amlodipine Besylate13 claims
- Pantoprazole Sodium13 claims
- Prednisone13 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Southwest Suffolk Medical PCRoslyn, NY
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Cassandra Marie O'Connor among 12,067 internal medicine physician records in New York
Cassandra Marie O'Connor, MD is one of 12,067 internal medicine physician records with a practice address in New York. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2021, is newer than 91% of them.
- NPI issued2021 · 91% of these records are older, 6% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 60% of these records are
- Graduated2020 · median 2002 among the 7,221 with a school on file
- Record last updated2024 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a New York practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
23 internal medicine physician records list a practice address in Roslyn
They are 23 of the 744 NPPES records with a practice address in Roslyn, and 12,067 internal medicine physician records in New York.
All 12,067 in New York → Every provider in Roslyn → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Joseph Ametrano, MDRoslyn, NY 115761942456454
- Viren Amin, M.D.Roslyn, NY 115761861661043
- Akram Boutros, M.D.Roslyn, NY 115761679773329
- Sundararaja Chandrasekaran, M.D.Roslyn, NY 115761598982209
- Maria Fedoseeva, MDRoslyn, NY 115761043599947
- Hc Glick, MDRoslyn, NY 115761215013990
- Kavita Goel, M.D.Roslyn, NY 115761356564348
- Nilsa Gutierrez, M.D.Roslyn, NY 115761922265446
Common questions
What is Cassandra Marie O'Connor, MD's NPI number?
Cassandra Marie O'Connor, MD's National Provider Identifier (NPI) is 1184200289, issued on Mar 20, 2021. An NPI identifies a provider in billing; it is not a license.
Where is Cassandra Marie O'Connor, MD located?
The NPPES record lists a practice address at 100 Port Washington Blvd, Roslyn, NY, 11576. Phone: (516) 562-6000. Providers update this record themselves, so call before visiting.
How can I verify Cassandra Marie O'Connor, MD's license?
NPPES lists New York license number 33108401, as entered by the provider. Search the NYS Education Department, Office of the Professions at https://www.op.nysed.gov/services/verifications/online-verification-searches. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Cassandra Marie O'Connor, MD prescribe under Medicare Part D?
In 2024, Cassandra Marie O'Connor, MD had 352 Medicare Part D claims for 128 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.