Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

William J Janssen, MD

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

William J Janssen, MD is a 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.

See every abbreviation used in this directory →

Claim this listing Report a problem Suggest an edit

Practice location Address checks out

1400 Jackson St
Denver, CO 80206-2761
Phone: (303) 388-4461
Fax: (303) 270-2206
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

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
Mailing address1400 Jackson St, Denver, CO 80206-2761

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

Other providers in Denver