William Charles O'Callahan Jr., MD

Primary specialty

Emergency Medicine PhysicianTaxonomy code 207P00000X

License

79001 Issued in MA

Practice address

5 Shrewsbury St Ste D
Holden, MA 01520-1960

Phone

(508) 829-3800

Fax

(508) 829-3802

NPI assigned

May 31, 2006

Sex

Male

Sole proprietor

No

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 1

Addresses

Medicare fee-for-service enrollment

Enrolled in MA

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Emergency Medicine

Education

University of Massachusetts Medical School, 1990

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Urgent Care Specialists PCGroup PAC ID 7315198488, 10 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Umass Memorial Medical Center/University Campus Hospital, Worcester, MA, CCN 220163

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• Urgent Care Specialists PC

  • Urgent Care Clinic/Center
  • Wilbraham, MA
  • NPI 1902157746

  Emergency Medicine

  Medicare reassignment Care Compare group NPD
• Urgent Care Specialists PC

  • Urgent Care Clinic/Center
  • Longmeadow, MA
  • NPI 1891579157

  Emergency Medicine

  NPD

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• Umass Memorial Medical Center, Inc.

  • General Acute Care Hospital
  • Worcester, MA
  • NPI 1831151455
  Care Compare affiliation

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1149033600000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1737417600000",
    "number": "1114964186",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "5 SHREWSBURY ST STE D",
            "city": "HOLDEN",
            "state": "MA",
            "postal_code": "015201960",
            "telephone_number": "508-829-3800",
            "fax_number": "508-829-3802"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "5 SHREWSBURY ST STE D",
            "city": "HOLDEN",
            "state": "MA",
            "postal_code": "015201960",
            "telephone_number": "508-829-3800",
            "fax_number": "508-829-3802"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "2040 Boston Rd Ste 5",
            "address_purpose": "LOCATION",
            "city": "Wilbraham",
            "state": "MA",
            "postal_code": "010951380",
            "country_code": "US",
            "telephone_number": "413-599-3800",
            "fax_number": "413-279-1900",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "2040 Boston Road",
            "address_2": "Ste 5",
            "address_purpose": "LOCATION",
            "city": "Wilbraham",
            "state": "MA",
            "postal_code": "010951380",
            "country_code": "US",
            "telephone_number": "413-599-3800",
            "fax_number": "413-279-1900",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "688 Bliss Road",
            "address_purpose": "LOCATION",
            "city": "Longmeadow",
            "state": "MA",
            "postal_code": "011061534",
            "country_code": "US",
            "telephone_number": "413-567-0011",
            "fax_number": "413-567-0013",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "O'CALLAHAN",
        "first_name": "WILLIAM",
        "middle_name": "CHARLES",
        "name_suffix": "Jr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2006-05-31",
        "last_updated": "2025-01-21",
        "certification_date": "2025-01-21",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207P00000X",
            "taxonomy_group": "",
            "desc": "Emergency Medicine",
            "state": "MA",
            "license": "79001",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Tracy Nguyen, DOCTOR OF PHARMACY
• Andrew Nickerson, ED.S., NCSP, LEP
• Vincent Noe
• Cynthia A Normandie, OD
• Neal M Novack, D.M.D.
• Carolyn O'Leary
• Michael Joseph Oconnell IV
• Faith Atieno Okhungu
• Kathleen Omara
• Oriol Home Health Inc

• Emergency Medicine Physician in Holden, MA
• Providers in Holden, MA by specialty
• Emergency Medicine Physician in Massachusetts

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jan 21, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.