MR. MARK LESLIE GAYNOR (LCSW) – Clinical Social Worker, NPI 1275515009

MR. MARK LESLIE GAYNOR (LCSW) is a healthcare provider. based in New haven, Connecticut. specializing in CLINICAL SOCIAL WORKER. They hold the professional credentials LCSW. They hold a License No. 000930 (CT). The NPI Number for MR. MARK LESLIE GAYNOR (LCSW) is 1275515009

Main info

Male
Sole Proprietor
51 Years Of Experience
Accepts Medicare Assignment
Name
MR. MARK LESLIE GAYNOR (LCSW)
NPI
1275515009
Phone
(203) 865-0865
Address
100 WHITNEY AVE
Enumeration Date
17 November 2005
Last Update Date
27 June 2018

Doctor Profile

Medical School Name
OTHER
Secondary Phone
2038650865
Graduation Year
1975 (51 years ago)
PAC ID
9638119902
Professional Enrollment ID
I20050505000641
Address ID
CT065101232NE100XXAVEX300
Data current as of
19 May 2026

Profile Insights

NPPES metrics only — not quality of care.

Methodology
Experience54
Completeness75
Years active:20State licenses:1Digital endpointsOther names

2,151 CLINICAL SOCIAL WORKER in CT

Loading map...

Provider Addresses for MR. MARK LESLIE GAYNOR (LCSW)

  • 110;100, Whitney Avenue, East Rock, Dixwell, New Haven, Connecticut, 06511, United States

    NEW HAVEN, CT 065101283

    Phone: (203) 865-0865

    Fax: (203) 865-0093

    Mailing address matches the actual address.

NPPES updates history

No NPPES updates recorded for this provider.

Prescription Activity

Loading prescription activity...

Open Payments (CMS)

No Open Payments data available for this provider.

This can happen when there are no reportable CMS Open Payments records.

Medicare Enrollment & Revalidation

Source: CMS public data · Not endorsed by CMS ·

Educational use only—not medical, billing, or legal advice.

PECOS enrollment status

Participating (accepts Medicare assignment)

Enrollment effective: 2005-05-05

PECOS data refreshed: 2026-05-27

Medicare revalidation (CMS due date list)

Due date not assigned yet

CMS is tracking this Medicare enrollment for revalidation, but has not published a due date.

Enrollment records

1

Earliest due date

Not assigned (TBD)

CMS data updated

2026-06-01

Revalidation progress

  1. Medicare enrolled
  2. On CMS revalidation list
  3. Due date assigned
  4. Revalidate in PECOS

CMS enrollment records

Enrollment IDTypeSpecialtyStateDue date
I20050505000641IClinical Social WorkerCTTBD

What to do next

  • No action required while the due date shows TBD.
  • Check the CMS Revalidation Lookup Tool periodically — CMS updates the list about every 60 days.
  • Do not submit a revalidation application in PECOS until CMS publishes a concrete due date.

Verify on CMS Revalidation Lookup Tool

Prepare CMS-855 application → · Look up this NPI in PECOS → · Verify on CMS PECOS

Medicare Utilization (FFS)

Source: CMS public data · Not endorsed by CMS · Beneficiary counts under 11 are suppressed in source data ·

Educational use only—not medical, billing, or legal advice.

No Medicare fee-for-service utilization data available for this provider in our database.

Insurance plans in this area (ZIP 06510)

Loading plans...

Reviews

All reviews are moderated before publication. Reviews reflect users' opinions; we do not verify the accuracy of individual reviews.

No reviews yet. Be the first to share your experience — your opinion helps families compare providers.

Frequently asked questions

What unique ID ties claims to MR. MARK LESLIE GAYNOR (LCSW)?
NPI 1275515009 is assigned to MR. MARK LESLIE GAYNOR (LCSW) under the national enumeration system.
Is MR. MARK LESLIE GAYNOR (LCSW)'s NPI currently valid?
The extract we use shows MR. MARK LESLIE GAYNOR (LCSW) as active.
What does MR. MARK LESLIE GAYNOR (LCSW) treat or focus on?
Patients typically see MR. MARK LESLIE GAYNOR (LCSW) under the specialty Clinical Social Worker. Clinical services aligned with this taxonomy classification.
Where is MR. MARK LESLIE GAYNOR (LCSW)'s primary listing?
We display New Haven, Connecticut because that is what the record indicates for MR. MARK LESLIE GAYNOR (LCSW).
Is this NPI for an individual or an organization?
This listing corresponds to an Individual Provider.

Similar Providers

111, Park Street, Downtown, New Haven, New Haven County, Connecticut, 06511, United States
NPI: 1811992431

BARBARA GOLDEN

Clinical Social Worker
106, Cove Street, Morris Cove, New Haven, South Central Connecticut Planning Region, Connecticut, 06512, United States
NPI: 1679567861

DIANE ROSEN (LCSW)

Clinical Social Worker
1890, Dixwell Avenue, Hamden, South Central Connecticut Planning Region, Connecticut, 06514, United States
NPI: 1417943317

MS. LINDA D VONO (LCSW)

Clinical Social Worker
291, Whitney Avenue, East Rock, New Haven, New Haven County, Connecticut, 06518, United States
NPI: 1639143969

MISS SUSAN E TOBENKIN (LCSW)

Clinical Social Worker
Cornell Scott Hill Health Center, 232, Cedar Street, Hill, New Haven, New Haven County, Connecticut, 06519, United States
NPI: 1760456008

AUGUSTUS PULLEN

Clinical Social Worker
35, Davis Street, Amity, West Hills, New Haven, Connecticut, 06515, United States
NPI: 1417925140

SUSAN FELDMAN (LCSW)

Clinical Social Worker
1 LONG WHARF DR
NPI: 1134197684

Unknown Individual

Clinical Social Worker
400, Columbus Avenue, Hill, New Haven, New Haven County, Connecticut, 06519, United States
NPI: 1174591499

RICHARD MALTZ

Clinical Social Worker
Dixwell Health Center, 226, Dixwell Avenue, Winchester Repeating Arms Historic District, New Haven, New Haven County, Connecticut, 06511, United States
NPI: 1417926536