Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

William J Janssen, MD

Individual provider Critical Care Medicine (Internal Medicine) Physician · NPI 1811905367

William J Janssen, MD is registered under Pulmonary Disease in Denver, Colorado. Graduated from Ohio State University College of Medicine in 1998, 28 years ago. Practices with National Jewish Health, a 246-clinician group, works from 2 locations and accepts Medicare assignment. Licensed in Colorado.

Years since qualifying
28
Trained at
Ohio State University College of Medicine
Licensed in
CO
In the registry since
2006
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

1400 Jackson St
Denver, CO 80206-2761
Phone: (303) 388-4461
Fax: (303) 270-2206
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 12605 E 16th Ave, Aurora, CO 80045-2545 — (720) 848-0000

Specialties & licences

Pulmonary Disease Physician (primary) Taxonomy 207RP1001X · Licence 41254 (CO)
Critical Care Medicine (Internal Medicine) Physician Taxonomy 207RC0200X · Licence 41254 (CO)

Record details

NPI number1811905367
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedAugust 3, 2006
Last updated in NPPESFebruary 23, 2021
Certification dateFebruary 23, 2021

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyPULMONARY DISEASE
Also practisesCRITICAL CARE (INTENSIVISTS)
Medical schoolOHIO STATE UNIVERSITY COLLEGE OF MEDICINE
Graduated 1998 (28 years in practice)
Group practice National Jewish Health — 246 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $32 1 payment · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at National Jewish Health

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 246 clinicians in the practice; 12 are shown here.

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