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

Mark Edward Sienko, MD

Individual provider Medical Oncology Physician · NPI 1932146552

Mark Edward Sienko, MD is a Medical Oncology in Sequim, Washington. Graduated from University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb) in 1989, 37 years ago. Practices with Multicare Health System, a 2,302-clinician group and accepts Medicare assignment. Licensed in Washington.

Years since qualifying
37
Trained at
University of Illinois College of Med (CHI/PEOR/ROCK/Chm-Urb)
Licensed in
WA
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 →

Practice location Address checks out

844 N 5th Ave
Sequim, WA 98382-3045
Phone: (360) 683-9895
Fax: (360) 582-5614
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Medical Oncology Physician (primary) Taxonomy 207RX0202X · Licence MD00046621 (WA)
Hematology & Oncology Physician Taxonomy 207RH0003X · Licence MD00046621 (WA)

Record details

NPI number1932146552
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJune 1, 2006
Last updated in NPPESFebruary 26, 2020
Certification dateFebruary 26, 2020

Medicare enrollment

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

Medicare specialtyMEDICAL ONCOLOGY
Also practisesHEMATOLOGY
Medical schoolUNIVERSITY OF ILLINOIS COLLEGE OF MED (CHI/PEOR/ROCK/CHM-URB)
Graduated 1989 (37 years in practice)
Group practice Multicare Health System — 2302 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

Other providers in Sequim