Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

NICHOLAS TSITSILIANOS MD
NPI 1386200780
Physical Medicine & Rehabilitation in Worcester, MA

Active since May 13, 2019PECOS EnrolledAccepts Medicare Assignment
123 SUMMER ST, WORCESTER, MA 01608(508) 363-5000 Get Directions Write a Review

NPPES record last updated: October 5, 2026. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Oct 5, 2026, Jul 15, 2019, May 13, 2019 (3 updates tracked since 2019).

About Nicholas Tsitsilianos Md NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

NICHOLAS TSITSILIANOS MD (NPI 1386200780) is an individual physical medicine & rehabilitation provider in Worcester, Massachusetts, licensed in Massachusetts (1020916) and active in the NPI registry since May 2019. He is enrolled in Medicare PECOS, is affiliated with Umass Memorial Healthalliance Hospitals, and is a graduate of Other (2019).

NPPES Registry Identity

NPI1386200780
Entity TypeIndividualMale
Primary Taxonomy208100000X
Provider Legal NameNICHOLAS TSITSILIANOSCredential: MD
Location Address123 SUMMER STWorcester, MA 01608-1216
Mailing Address123 Summer StWorcester, MA 01608-1216
Sole ProprietorNo
Medical School CMSOtherGraduated 2019
Enumeration DateMay 13, 2019
Last NPPES UpdateOctober 5, 20263 updates tracked since enumeration
NPPES CertifiedOctober 5, 2026
✔ NPI 1386200780 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyPhysical Medicine & RehabilitationAllopathic & Osteopathic Physicians
Taxonomy Code208100000X
License✔ Licensed in MA · 1020916
Definition
Physical medicine and rehabilitation, also referred to as rehabilitation medicine, is the medical specialty concerned with diagnosing, evaluating, and treating patients with physical disabilities. These disabilities may arise from conditions affecting the musculoskeletal system such as neck and back pain, sports injuries, or other painful conditions affecting the limbs, such as carpal tunnel syndrome. Alternatively, the disabilities may result from neurological trauma or disease such as spinal cord injury, head injury or stroke. A physician certified in physical medicine and rehabilitation is often called a physiatrist. The primary goal of the physiatrist is to achieve maximal restoration of physical, psychological, social and vocational function through comprehensive rehabilitation. Pain management is often an important part of the role of the physiatrist. For diagnosis and evaluation, a physiatrist may include the techniques of electromyography to supplement the standard history, physical, x-ray and laboratory examinations. The physiatrist has expertise in the appropriate use of therapeutic exercise, prosthetics (artificial limbs), orthotics and mechanical and electrical devices.
Also ListedPhysical Medicine & Rehabilitation · Sports MedicineTaxonomy 2081S0010X · License 1020916 (MA)
123 SUMMER ST, Worcester, MA 01608

Accepted Insurance

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

Nicholas Tsitsilianos 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.

PECOS PAC ID446780670
PECOS Enrollment IDI20250204000315
Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

2

Medicare enrollment records show Nicholas Tsitsilianos reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Internal Medicine
55 LAKE AVE N
Worcester, MA 01655
  • Reassigned Medicare billing, Massachusetts enrollment
  • 2,902 clinicians in this Medicare group
Sports Medicine
20 WALNUT ST STE 14
Wellesley, MA 02481
  • Reassigned Medicare billing, Massachusetts enrollment
  • 3 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.

Hospital Affiliations CMS Care Compare 5

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Umass Memorial Healthalliance Hospitals

Acute Care Hospitals · Leominster, MA
2/5 CMS rating
OwnershipVoluntary non-profit - Other
CMS Certification Number220001
Location60 Hospital RoadLeominster, MA 01453 · Worcester County
Emergency services

Umass Memorial Health - Harrington Hospital

Acute Care Hospitals · Southbridge, MA
3/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220019
Location100 South StreetSouthbridge, MA 01550 · Worcester County
Emergency services

Milford Regional Medical Center

Acute Care Hospitals · Milford, MA
4/5 CMS rating
OwnershipVoluntary non-profit - Other
CMS Certification Number220090
Location14 Prospect StreetMilford, MA 01757 · Worcester County
Emergency services Birthing friendly

Umass Memorial Medical Center/University Campus

Acute Care Hospitals · Worcester, MA
4/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number220163
Location55 Lake Avenue NorthWorcester, MA 01655 · Worcester County
Emergency services Birthing friendly

St Vincent Hospital

Acute Care Hospitals · Worcester, MA
2/5 CMS rating
OwnershipProprietary
CMS Certification Number220176
Location123 Summer StreetWorcester, MA 01608 · Worcester County
Emergency services Birthing friendly

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.

Hospitalist
123 SUMMER ST
WORCESTER, MA 01608
Internal Medicine
123 SUMMER ST
WORCESTER, MA 01608
Student in an Organized Health Care Education/Training Program
123 SUMMER ST
WORCESTER, MA 01608
Nurse Anesthetist, Certified Registered
123 SUMMER ST
WORCESTER, MA 01608
Pathology (Anatomic Pathology & Clinical Pathology)
123 SUMMER ST
WORCESTER, MA 01608
Obstetrics & Gynecology (Obstetrics)
123 SUMMER ST, SUITE 560
WORCESTER, MA 01608
Physician Assistant
123 SUMMER ST
WORCESTER, MA 01608
Midwife
123 SUMMER ST
WORCESTER, MA 01608

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 Nicholas Tsitsilianos's NPI number?

The NPI number for Nicholas Tsitsilianos is 1386200780. It was assigned to this individual provider in the NPPES registry on May 13, 2019.

Where is Nicholas Tsitsilianos located?

Nicholas Tsitsilianos practices at 123 Summer St, Worcester, MA 01608. The listed phone number is (508) 363-5000.

What is Nicholas Tsitsilianos's specialty?

The primary specialty registered for this NPI is Physical Medicine & Rehabilitation with taxonomy code 208100000X.

Is Nicholas Tsitsilianos enrolled in Medicare?

Yes. Nicholas Tsitsilianos 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 Nicholas Tsitsilianos's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Nicholas Tsitsilianos reassigns Medicare benefits to 2 organizations: Umass Memorial Medical Group Inc (Worcester, MA) and Boston Sports & Spine LLC (Wellesley, MA). 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 Nicholas Tsitsilianos's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

What insurance does Nicholas Tsitsilianos accept?

Health plans from Taro Health list Nicholas Tsitsilianos as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.

Is Nicholas Tsitsilianos affiliated with any hospitals?

According to CMS data, Nicholas Tsitsilianos is affiliated with Umass Memorial Healthalliance Hospitals, Umass Memorial Health - Harrington Hospital, Milford Regional Medical Center, Umass Memorial Medical Center/University Campus and St Vincent Hospital.

When was this NPI record last updated?

The NPPES record for Nicholas Tsitsilianos was last updated on October 5, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 24 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.