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DR. ANDREW RICHARD WILLIAMS M.D.
NPI 1245641869
Internal Medicine in Pasadena, CA

Active since May 16, 2014PECOS EnrolledAccepts Medicare Assignment
100 W CALIFORNIA BLVD, PASADENA, CA 91105(626) 397-5000 Get Directions Write a Review

NPPES record last updated: January 15, 2026. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: Jan 15, 2026, Jul 2, 2025 (2 updates tracked since 2025).

About Dr. Andrew Richard Williams M.d. NPPES

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

DR. ANDREW RICHARD WILLIAMS M.D. (NPI 1245641869) is an individual internal medicine provider in Pasadena, California, licensed in California (A135707) and active in the NPI registry since May 2014. He is enrolled in Medicare PECOS and is a graduate of Other (2013).

NPPES Registry Identity

NPI1245641869
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameDR. ANDREW RICHARD WILLIAMSCredential: M.D.
Location Address100 W CALIFORNIA BLVDPasadena, CA 91105-3010
Mailing AddressPo Box 35380Las Vegas, NV 89133-5380 · (702) 579-3203
Phone(626) 397-5000
Sole ProprietorNo
Medical School CMSOtherGraduated 2013
Enumeration DateMay 16, 2014
Last NPPES UpdateJanuary 15, 20262 updates tracked since enumeration
NPPES CertifiedJanuary 15, 2026
✔ NPI 1245641869 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in CA · A135707
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
100 W CALIFORNIA BLVD, Pasadena, CA 91105
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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

Dr. Andrew Richard Williams M.d. 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 ID9133429079
PECOS Enrollment IDI20151130000442
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 Andrew Williams reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

The Huntington Medical Foundation
Same address
Internal Medicine
100 W CALIFORNIA BLVD
Pasadena, CA 91105
  • Reassigned Medicare billing, California enrollment
  • 204 clinicians in this Medicare group
NPI 1154467181 (626) 397-8335
Healthcare Partners Affiliates Medical Group
10 mi
Internal Medicine
1120 W WASHINGTON BLVD
Los Angeles, CA 90015
  • Reassigned Medicare billing, California enrollment
  • 2,052 clinicians in this Medicare group
NPI 1659312593 (213) 623-2225

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 91105 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$142.39 typical visit price
range $62.96 – $187.60
Typical copayment $35.59 (range $15.74 – $46.90)
Most-billed visit code 99204
Established Patient
$109.96 typical visit price
range $20.84 – $153.61
Typical copayment $27.49 (range $5.21 – $38.40)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

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.

SARAH STEPHENS NP
Nurse Practitioner (Acute Care)
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-8300
ROMELIA JALEH BATANG GARCIA RNFA
Registered Nurse (Registered Nurse First Assistant)
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-5012
DR. RICHARD A. REED MEDICAL DOCTOR
Radiology (Diagnostic Radiology)
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-5139
DR. HENRY LEVENSON M.D.
Pain Medicine (Pain Medicine)
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 256-6010
PASADENA HOSPITAL ASSOCIATION, LTD.
Rehabilitation Unit
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-5555
ANIL K HANUMAN D,O.
Hospitalist
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-8300
DR. NICHOLAS WITHROW GRECO M.D.
Emergency Medicine
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 397-5112
DR. MINDY EVE TITTIGER M.D.
Internal Medicine
100 W CALIFORNIA BLVD
PASADENA, CA 91105
Los Angeles County (626) 352-1444

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 Andrew Williams's NPI number?

The NPI number for Andrew Williams is 1245641869. It was assigned to this individual provider in the NPPES registry on May 16, 2014.

Where is Andrew Williams located?

Andrew Williams practices at 100 W California Blvd, Pasadena, CA 91105. The listed phone number is (626) 397-5000.

What is Andrew Williams's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Andrew Williams enrolled in Medicare?

Yes. Andrew Williams 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 Andrew Williams's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Andrew Williams reassigns Medicare benefits to 2 organizations: The Huntington Medical Foundation (Pasadena, CA) and Healthcare Partners Affiliates Medical Group (Los Angeles, CA). 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 Andrew Williams'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 Andrew Williams was last updated on January 15, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 9 months 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.