Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Michael Kleyn, M.D.

Critical Care Medicine (Internal Medicine) Physician in Mountainside, NJ · enumerated 2009.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1275761207

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Registry record

Entity type Individual (Type 1)

Name Michael Kleyn

Credential M.D.

Sex Male

Practice address Mountainside, NJ, 07092

Phone (718) 207-3140

Enumeration date Jun 29, 2009

Last updated in NPPES Dec 8, 2015

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

207RC0200X Critical Care Medicine (Internal Medicine) Physician Allopathic & Osteopathic Physicians · License 25MA09504100 (NJ) Primary

207RC0200X Critical Care Medicine (Internal Medicine) Physician Allopathic & Osteopathic Physicians · License ME 122780 (FL) Secondary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

Where does Michael Kleyn practice?

The practice location on file with NPPES is in Mountainside, NJ. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Michael Kleyn?

The National Provider Identifier (NPI) for Michael Kleyn is 1275761207, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-12-08.