Quick answers
- Does Gregory W. Mattingley accept Medicare assignment?
- Yes. Medicare's clinician data says Gregory W. Mattingley 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 Gregory W. Mattingley see?
- In 2024, CMS data shows 141 Original Medicare patients and 432 services for Gregory W. Mattingley. This counts Original Medicare only and measures volume, not quality.
- What is Gregory W. Mattingley's NPI number?
- 1215933379. 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 Gregory W. Mattingley, 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 patients | 141 |
|---|---|
| Services billed to Medicare | 432 |
| Different services or procedures | 7 |
| Participating Medicare provider | Yes |
| Average age of these patients | 65 |
Most frequent services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)165 services
- Psychotherapy with evaluation and management visit, 30 minutes (90833)126 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)78 services
- Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)22 services
- Psychiatric diagnostic evaluation with medical services (90792)20 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- Depression75%
- Anxiety75%
- High cholesterol70%
- High blood pressure60%
- Arthritis43%
- Diabetes28%
Practice locations
Addresses where Gregory W. Mattingley is enrolled with Medicare (CMS data updated October 2, 2026).
- 4801 Weldon Spring Pkwy, Suite 300St Charles, MO 63304
- 4801 Weldon Spring Pkwy, Suite 300Weldon Spring, MO 63304 (636) 949‑5760
Group practices
Medicare enrollment lists Gregory W. Mattingley as a member of this group (CMS data updated October 2, 2026).
- St. Charles Psychiatric Associates, Inc.8 clinicians in the group
Specialties
- Psychiatryprimary
Other psychiatrists in Missouri
Clinicians with the same Medicare primary specialty in Missouri — not a recommendation.
Other clinicians in St. Charles Psychiatric Associates, Inc.
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Washington University School Of Medicine |
| Graduation year | 1989 (37 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1215933379 |
| 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
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- 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