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Family Practice

Hillard Zallen, MD

Sees patients in Longmont, CO · Colorado

Summary

Dr. Hillard Zallen, MD is a family doctor at 2345 Bent Way, Kaiser Permanente Longmont Med, Longmont, CO 80503. Phone: (303) 338-4545. Accepts Medicare assignment. In 2024, Hillard Zallen had 18 Original Medicare patients and 30 services. NPI 1225157712. Source: CMS National Downloadable File, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

  • Specialty: Family doctor (Medicare lists Family Practice)
  • Address: 2345 Bent Way, Kaiser Permanente Longmont Med, Longmont, CO 80503 · Directions
  • Phone: (303) 338‑4545
  • Medicare: Accepts Medicare assignment
  • Group practice: Colorado Permanente Medical Group PC
  • Medical school: University Of New Mexico School Of Medicine · graduated 1999 (27 years since medical school)
  • Gender (as listed): Male

From official Medicare data

This page shows what Medicare's official clinician data says about Hillard Zallen, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Hillard Zallen accept Medicare assignment?
Yes. Medicare's clinician data says Hillard Zallen accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Hillard Zallen see?
In 2024, CMS data shows 18 Original Medicare patients and 30 services for Hillard Zallen. This counts Original Medicare only and measures volume, not quality.
What is Hillard Zallen's NPI number?
1225157712. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Hillard Zallen, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients18
Services billed to Medicare30
Different services or procedures14
Participating Medicare providerYes
Average age of these patients63

Practice locations

Addresses where Hillard Zallen is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Hillard Zallen as a member of this group (CMS data updated October 2, 2026).

  • Colorado Permanente Medical Group PC1,327 clinicians in the group

Specialties

Find other Family Practice doctors in Colorado →

Other family doctors in Longmont

Clinicians with the same Medicare primary specialty in Longmont, CO — not a recommendation.

All family doctors in Longmont →

Other clinicians in Colorado Permanente Medical Group PC

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolUniversity Of New Mexico School Of Medicine
Graduation year1999 (27 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1225157712
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  2. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  3. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  4. Medicare Care Compare — official Medicare tool to look up clinicians