Quick answers
- Which hospitals does Timothy M. Niessen work at?
- Medicare's official clinician data lists Timothy M. Niessen at 1 hospital: The Johns Hopkins Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Timothy M. Niessen see patients?
- Medicare's clinician data lists 2 practice locations, including Baltimore, MD. Call before your visit to confirm the address.
- What is Timothy M. Niessen's specialty?
- Medicare lists Internal Medicine as the primary specialty.
- Does Timothy M. Niessen accept Medicare assignment?
- Medicare's clinician data says Timothy M. Niessen may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- What is the phone number for Timothy M. Niessen?
- (410) 955-5000, as listed in official Medicare / NPI Registry data.
- What is Timothy M. Niessen's NPI number?
- 1730322900. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Timothy M. Niessen works
Medicare's Facility Affiliation Data lists Timothy M. Niessen at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- The Johns Hopkins HospitalBaltimore, MD · Acute Care Hospital · CCN 210009
Practice locations
Addresses where Timothy M. Niessen is enrolled with Medicare (CMS data updated 2026-10-02).
- 600 N Wolf StBaltimore, MD 21287 (410) 955‑5000
- 600 N Wolfe St, Blalock 266Baltimore, MD 21287 (410) 502‑4340
Group practices
Medicare enrollment lists Timothy M. Niessen as a member of these groups (CMS data updated 2026-10-02).
- Johns Hopkins University2,909 clinicians in the group
- Johns Hopkins University713 clinicians in the group
Specialties
- Internal Medicineprimary
Other internal medicine doctors in Baltimore
Clinicians with the same Medicare primary specialty in Baltimore, MD — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Johns Hopkins University School Of Medicine |
| Graduation year | 2009 |
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| NPI (National Provider Identifier) | 1730322900 |
| Corrections | Report 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
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians