Doctor profile · Federal record

Dr. William Mills, M.D.

Emergency Medicine Physician (CMS: Emergency Medicine) · Walnut Creek, CA

  • NPI 1497779300
  • Accepts Medicare
  • MIPS 86.3 / 100 · 2023
  • 33 yrs in practice
  • Male
  • Group practice
  • No sanctions

Practice & contact

NPPES Updated May 11, 2026
Primary practice
1601 Ygnacio Valley RD
Walnut Creek, CA 945983122
(925) 939-3000
Mailing address
2100 Powell St, Suite 900
Emeryville, CA 946081826

Credentials & registration

NPPES · NUCC
NPI registered
July 2006 — 20 yrs on file
Profile last updated
October 26, 2007
Year of graduation
1993 — 33 yrs since
Specialty taxonomy
207P00000X — NUCC code
State license (1)
California #A62432
Medicaid
CA #00A624320

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1497779300. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
420
Distinct HCPCS
4
Medicare allowed
$67,198
HCPCS Description Services Patients Avg allowed
99285 Emergency department visit with high level of medical decision making 231 227 $188
99284 Emergency department visit with moderate level of medical decision making 88 88 $130
99291 Critical care, first 30-74 minutes 51 49 $234
93010 Routine electrocardiogram (ecg) using at least 12 leads with interpretation and report only 50 47 $9

In context: peer comparison

Among 26 peers in Walnut Creek Emergency Medicine Physician, average services per provider: 87. This provider delivers 4.8× the peer median.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$50
Transactions
1
Manufacturers
1
Payer (manufacturer) Industry Txns Amount
Globus Medical, INC. 1 $50.33

By nature of payment

Food and Beverage
$50

Medicare Part D · 2023

Top prescriptions

CMS Part D Prescriber
Total claims
42
Patients
42
Total drug cost
$494
Drug Type Claims Patients Total cost
Hydrocodone-Acetaminophen (Hydrocodone/Acetaminophen) Brand 17 17 $85
Cephalexin Generic 14 14 $183
Nitrofurantoin Mono-Macro (Nitrofurantoin Monohyd/M-Cryst) Brand 11 11 $225

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. William Mills's medical specialty?
Dr. William Mills practices Emergency Medicine Physician in Walnut Creek, CA.
Where does Dr. William Mills practice?
Dr. William Mills practices at 1601 Ygnacio Valley RD, Walnut Creek, CA 945983122. Office phone: 9259393000.
What is Dr. William Mills's NPI?
Dr. William Mills's National Provider Identifier (NPI) is 1497779300, issued by NPPES.
Does Dr. William Mills accept Medicare assignment?
Yes. Dr. William Mills accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.
What procedures does Dr. William Mills commonly perform?
Top Medicare-reported procedures in 2023: Emergency department visit with high level of medical decision making (HCPCS 99285); Emergency department visit with moderate level of medical decision making (HCPCS 99284); Critical care (HCPCS 99291). Source: CMS Medicare Physician & Other Practitioners file.