MARY G DIANA MD
NPI 1962445684
Obstetrics & Gynecology in Greenwich, CT
About Mary G Diana Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARY G DIANA MD (NPI 1962445684) is an individual obstetrics & gynecology provider in Greenwich, Connecticut, licensed in New York (200058) and active in the NPI registry since June 2006. She is enrolled in Medicare PECOS and is a graduate of Columbia University College Of Physicians And Surgeons (1992).
NPPES Registry Identity
Specialties & Licenses
Other Identifiers 3
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Mary G Diana Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
6Medicare enrollment records show Mary Diana reassigns Medicare billing to 6 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Greenwich, CT 06830
- Reassigned Medicare billing, Connecticut enrollment
- 268 clinicians in this Medicare group
Bronx, NY 10467
- Reassigned Medicare billing, New York enrollment
- 5,251 clinicians in this Medicare group
New Haven, CT 06519
- Reassigned Medicare billing, Connecticut enrollment
- 3,728 clinicians in this Medicare group
Middletown, NY 10941
- Reassigned Medicare billing, New York enrollment
- 434 clinicians in this Medicare group
Niskayuna, NY 12309
- Reassigned Medicare billing, New York enrollment
- Medicare enrollment name: Obgyn Hospitalist Medical Services Of New York PC
- 125 clinicians in this Medicare group
Greenville, SC 29607
- Reassigned Medicare billing, Connecticut enrollment
- 37 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 06830 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
GREENWICH, CT 06830
GREENWICH, CT 06830
GREENWICH, CT 06830
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 Mary Diana's NPI number?
The NPI number for Mary Diana is 1962445684. It was assigned to this individual provider in the NPPES registry on June 13, 2006.
Where is Mary Diana located?
Mary Diana practices at 5 Perryridge Rd, Greenwich, CT 06830. The listed phone number is (203) 863-3000.
What is Mary Diana's specialty?
The primary specialty registered for this NPI is Obstetrics & Gynecology with taxonomy code 207V00000X.
Is Mary Diana enrolled in Medicare?
Yes. Mary Diana is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Mary Diana's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mary Diana reassigns Medicare benefits to 6 organizations: Greenwich Hospital (Greenwich, CT), Montefiore Medical Center (Bronx, NY), Yale University (New Haven, CT), Crystal Run Healthcare Physicians LLP (Middletown, NY), Obgyn Hospitalist Medical Services Of New York, P.C. (Niskayuna, NY) and 1 more organization, listed in the Medicare section above. Each 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 Mary Diana's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Mary Diana was last updated on September 25, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 37 days 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.
# Mary G Diana, MD · NPI 1962445684
Obstetrics & Gynecology physician in Greenwich, Connecticut. Individual provider, active in the CMS NPPES registry since June 13, 2006.
## Identity
- **NPI:** 1962445684 (Entity type: Individual)
- **Enumerated:** June 13, 2006
- **Primary specialty:** Obstetrics & Gynecology · taxonomy 207V00000X
- **State license:** 200058 (New York)
- **Sole proprietor:** No
## Practice location
- **Address:** 5 PERRYRIDGE RD, Greenwich, CT 06830-4697
- **Phone:** (203) 863-3000
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 6 organizations under Medicare reassignment (form CMS-855R): Greenwich Hospital (NPI 1609846088, Greenwich, CT); Montefiore Medical Center (NPI 1063525152, Bronx, NY); Yale University (NPI 1124148887, New Haven, CT); Crystal Run Healthcare Physicians LLP (NPI 1952376410, Middletown, NY); Obgyn Hospitalist Medical Services Of New York, P.C. (NPI 1518285055, Niskayuna, NY); and 1 more · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Columbia University College Of Physicians And Surgeons, class of 1992
## Record status
- **NPPES last updated:** September 25, 2026
- **Other identifiers:** Other 0667910001 (NY); Medicaid 01659383 (NY); Other P00413156 (NY)
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Source: [NPI Profile](https://npiprofile.com/npi/1962445684) · Data from the CMS NPPES public registry.