Willowdale Internal Medicine Associates LLC
NPI 1649300161 · Internal Medicine Physician · Kennett Square, PA
Enrolled with Medicare as Part B Supplier - Clinic/Group Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Willowdale Internal Medicine Associates LLC is a Internal Medicine Physician organization in Kennett Square, PA (NPI 1649300161).
Provider details
- NPI number
- 1649300161
- Entity type
- Organization
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Organization subpart
- No
- Authorized official
- Karl Zimmerman, Owner(610) 444-1212
- License
- MD056655L (PA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Other names (DBA / former)
- Former legal business name
- Karl Zimmerman MD LLC
Registry dates
- Enumerated
- 2007-03-06
- Last updated
- 2015-02-17
Frequently asked questions
- What is Willowdale Internal Medicine Associates LLC's NPI number?
- Willowdale Internal Medicine Associates LLC's National Provider Identifier (NPI) is 1649300161, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What type of organization is Willowdale Internal Medicine Associates LLC?
- Willowdale Internal Medicine Associates LLC is classified in the NPPES registry as Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Willowdale Internal Medicine Associates LLC located?
- Willowdale Internal Medicine Associates LLC's practice location on file with NPPES is 127 W Street Rd, Kennett Square, PA 19348-1698.
- What is Willowdale Internal Medicine Associates LLC's phone number?
- The practice phone number listed in the NPPES registry for Willowdale Internal Medicine Associates LLC is (610) 444-1212.
- Does Willowdale Internal Medicine Associates LLC accept Medicare?
- Willowdale Internal Medicine Associates LLC is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Who is the authorized official for Willowdale Internal Medicine Associates LLC?
- The authorized official listed on Willowdale Internal Medicine Associates LLC's NPPES record is Karl Zimmerman, Owner. The authorized official registers and maintains the organization's NPI and is not necessarily its owner.
- Is Willowdale Internal Medicine Associates LLC's NPI active?
- Yes — Willowdale Internal Medicine Associates LLC's NPI (1649300161) is active in the NPPES registry as of the last update on 2015-02-17.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.