What is Leo Cass's NPI number?

Leo Cass's National Provider Identifier (NPI) is 1033158795, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.

What is Leo Cass's specialty?

Leo Cass is listed in the NPPES registry with a primary specialty of Specialist (Other Service Providers).

Where is Leo Cass located?

Leo Cass's practice location on file with NPPES is 223 Swanton St, Winchester, MA 01890-1968.

What is Leo Cass's phone number?

The practice phone number listed in the NPPES registry for Leo Cass is (781) 721-5025.

Does Leo Cass accept Medicare?

Leo Cass is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.

Is Leo Cass's NPI active?

Yes — Leo Cass's NPI (1033158795) is active in the NPPES registry as of the last update on 2018-03-17.

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Leo Cass, M.D.

NPI 1033158795 · Specialist · Winchester, MA

Leo Cass, M.D. is a Specialist provider in Winchester, MA (NPI 1033158795).

Provider details

NPI number: 1033158795
Entity type: Individual
Primary specialty: SpecialistOther Service Providers
Credential: M.D.
Sex: Male
Sole proprietor: No
License: 33744 (MA)

Practice location

223 Swanton St

Winchester, MA 01890-1968

Phone: (781) 721-5025

Fax: (781) 729-2297

Street-level locationGet directions

More MA providers

Mailing address

Po Box 2706

Woburn, MA 01888-1306

Specialties & taxonomies

SpecialistPrimary174400000XLicense 33744 (MA)
Other Service Providers

Additional practice locations (1)

184 Swanton St
Winchester, MA 01890-1921
Phone: (781) 721-5025
Fax: (781) 729-2297

Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)

Profile Score

Detailed profile(95/100 index)

A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.

Registry tenure38% of score
20 yrs in NPPES registry
Profile completeness38% of score
100% of core fields populated
Practice footprint23% of score
2 documented practice locations

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.

What this provider prescribes (Medicare Part D)

Top drugs by Medicare Part D claim volume, 2024 · 33 distinct drugs on file.

Drug	Part D claims (2024)
Sertraline Hcl	192
Metformin Hcl	186
Atorvastatin Calcium	149
Metoprolol Succinate	148
Mirtazapine	129
Lisinopril	107
Labetalol Hcl	106
Torsemide	106
Furosemide	105
Tamsulosin Hcl	87

Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do not include cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means no Part D record, never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.

Enumerated: 2006-06-06
Last updated: 2018-03-17

Frequently asked questions

What is Leo Cass's NPI number?: Leo Cass's National Provider Identifier (NPI) is 1033158795, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
What is Leo Cass's specialty?: Leo Cass is listed in the NPPES registry with a primary specialty of Specialist (Other Service Providers).
Where is Leo Cass located?: Leo Cass's practice location on file with NPPES is 223 Swanton St, Winchester, MA 01890-1968.
What is Leo Cass's phone number?: The practice phone number listed in the NPPES registry for Leo Cass is (781) 721-5025.
Does Leo Cass accept Medicare?: Leo Cass is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
Is Leo Cass's NPI active?: Yes — Leo Cass's NPI (1033158795) is active in the NPPES registry as of the last update on 2018-03-17.

Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.

Provider details

Practice location

Mailing address

Specialties & taxonomies

Additional practice locations (1)

Profile Score

What this provider prescribes (Medicare Part D)

Registry dates

Frequently asked questions

Specialties & taxonomies

Additional practice locations (1)

Profile Score

What this provider prescribes (Medicare Part D)

Frequently asked questions