Dr. Mark C. Walker I, MD
- Medicare services, 2021
- 462
- Part D claims, 2024
- 356
- Industry payments
- $957
- Affiliated sites
- 1
- Medical group
- 1
- Practice address
- 3235 Sw 34th St, Ocala, FL 34474
- Practice phone
- Call (352) 431-3940
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Harmony United Florida
Ocala, Florida
Find Dr. Walker's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. Mark C. Walker I is a psychiatrist in Ocala, Florida
Dr. Walker practices at Harmony United Florida in Ocala, Florida.
Dr. Walker's NPI, 1427318864, was assigned on May 19, 2012. Dr. Walker graduated from American University of the Caribbean School of Medicine in 1990. Dr. Walker holds Florida license ME108732.
- NPI
- 1427318864NPI Registry (opens in a new tab)
- Medicare PAC ID
- 8729224878
- NPI enumeration date
- May 19, 2012
- NPI status
- Active
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
- Practice phone
- (352) 431-3940
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Estimated age
- 62
- Medical school graduation
- 1990
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; Dmand AI Practice Data; and Doctors and Clinicians National Downloadable File (CMS)
Dr. Mark C. Walker I practices at Harmony United Florida in Ocala, Florida
Dr. Walker's primary practice is Harmony United Florida, at 3235 Sw 34th St, Ocala, FL 34474 in Marion County. The practice phone is (352) 431-3940.
- Harmony United Florida3235 Sw 34th St, Ocala, FL 34474 · Marion CountyPhone(352) 431-3940
Sources: NPPES NPI Registry (CMS); and Dmand AI Practice Data
Dr. Mark C. Walker I is affiliated with 2 sites of care and 1 medical group
Dr. Walker's primary practice is Harmony United Florida in Ocala, Florida. The medical group on file is Harm Reduction Center. Dmand AI also links Dr. Walker to 1 more group practice or clinic, named with a free account.
Sources: NPPES NPI Registry (CMS); Dmand AI Practice Data; and Dmand AI Affiliation Data
Dmand AI tracks the EHR system at Dr. Mark C. Walker I's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Walker practices. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Harmony United Florida | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. Mark C. Walker I is one of 1,975 psychiatrists in Florida
Psychiatry is Dr. Walker's primary specialty in the NPI Registry, under taxonomy code 2084P0800X. Dr. Walker is licensed in Florida.
Specialties and state licenses
- Psychiatry, FloridaPrimary
Psychiatrists near Dr. Walker
Counts of psychiatrists with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. Mark C. Walker I billed Medicare for 462 services in 2021
CMS data shows 462 Medicare services from Dr. Walker across 3 procedure codes in 2021. Medicare paid $33,417 for them. Every service was in an office.
Dr. Walker's Medicare services by type, 2020 to 2021
- 2020
- 2021
- Tests and treatments
- 2020: 862021: 231169%
- Office and hospital visits
- 2020: 822021: 231182%
Dr. Walker compared with the Florida median for psychiatrists, 2021
- Dr. Walker
- Florida median
- Medicare services
- 462vs 2042.3 times
- Part D claims
- 256vs 2407% above
Medians across 1,952 psychiatrists in Florida with Dmand AI profiles that report each measure.
Dr. Walker's most billed Medicare procedure codes, 2021
CMS publishes codes billed for 11 or more Medicare patients. Each label is the code family; CPT descriptions are licensed by the AMA.
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Sources: Medicare Physician & Other Practitioners - by Provider and Service (CMS), 2024 data; and Dmand AI Peer Benchmarks
Dr. Mark C. Walker I's patients have a median age of 56
Across all payers, Dmand AI patient panel data puts Dr. Walker's median patient age at 56, with 57% women.
Dr. Walker's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 56
Patient panel by sex, all payers
- Women57%
- Men43%
Source: Dmand AI Patient Panel Data
Dr. Mark C. Walker I wrote 356 Medicare Part D claims in 2024
In 2024, Dr. Walker wrote 356 Medicare Part D claims for 31 patients. 100% of them were for generic drugs. CMS names the drug for 256 of them, across 12 drugs with 11 or more claims each, at $2,571 in total drug cost. In 2023, CMS named 19 claims across 1 drug.
Dr. Walker's Part D claims by kind of drug, 2024
- Generic355 claims100%
- Brand-name and other1 claims0%
Dr. Walker's most prescribed drugs by claims, 2024
CMS names a drug when it has 11 or more claims. Share is of the claims for drugs CMS names.
Drug classes CMS tracks in Dr. Walker's Part D claims, 2024
- Antipsychotics, patients 65 and over6%22 of 356 claims
Share of all Part D claims for each drug class CMS reports on. Classes with no claims are left out.
Part D claims for drugs CMS names, 2023 to 2024
- 2023
- 2024
- Claims for drugs CMS names
- 2023: 192024: 2561247%
Drugs named by CMS: 12 in 2024, 1 in 2023.
Sources: Medicare Part D Prescribers - by Provider and Drug (CMS), 2024 data, released May 6, 2026; and Medicare Part D Prescribers - by Provider (CMS), 2024 data
Dr. Mark C. Walker I offers telehealth to Medicare patients
Dr. Walker accepts Medicare assignment, so Medicare's approved amount is taken as full payment. CMS lists Dr. Walker as offering telehealth.
- Accepts Medicare assignment
- Yes
- Offers telehealth
- Yes
Source: Doctors and Clinicians National Downloadable File (CMS)
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Dr. Mark C. Walker I received $957 in industry payments from 2016 to 2021
CMS Open Payments shows 54 general payments to Dr. Walker from 15 drug and device companies from 2016 to 2021. Food and beverage make up the largest share, 100% of the total. Otsuka America Pharmaceutical, Inc. paid the most, $244.
General payments to Dr. Walker by program year, 2016 to 2021
Companies that paid Dr. Walker the most, 2016 to 2021
Share is of all general payments to this clinician.
Source: Open Payments (CMS), 2025 data, released July 7, 2026
Dr. Mark C. Walker I graduated from American University of the Caribbean School of Medicine
Dr. Walker graduated from American University of the Caribbean School of Medicine in 1990.
- Medical school
Source: Dmand AI Professional Profile Data
Dr. Mark C. Walker I accepts plans from 6 insurance carriers
Dr. Walker is in network with 6 carriers, including Aetna, United Healthcare and CMS Medicare. PPO plans come from the most carriers, 4. Check the plan with the practice before a visit.
- Aetna
- United Healthcare
- CMS Medicare
- EMI Health
- GA State Medicaid
- Pacific Source Health Plans
Plan types Dr. Walker accepts, by number of carriers
- PPO4
- Medicare3
- HMO2
- POS2
- EPO1
- Medicaid1
Source: Dmand AI Insurance Network Data
Sources for Dr. Mark C. Walker I's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice Data |
| Primary practice, affiliations and health system | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Practice DataDmand AI Affiliation Data |
| Medicare services and procedure codes | Medicare Physician & Other Practitioners - by Provider and Service (CMS) (opens in a new tab) |
| State medians for the same specialty | Dmand AI Peer Benchmarks |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Part D prescribing | Medicare Part D Prescribers - by Provider and Drug (CMS) (opens in a new tab)Medicare Part D Prescribers - by Provider (CMS) (opens in a new tab) |
| MIPS scores, telehealth, assignment and procedure percentiles | Doctors and Clinicians National Downloadable File (CMS) (opens in a new tab) |
| Industry payments | Open Payments (CMS) (opens in a new tab) |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. Mark C. Walker I
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. Mark C. Walker I's NPI number?
Dr. Mark C. Walker I's NPI number is 1427318864. It was assigned on May 19, 2012, and it is active in the NPI Registry.
What kind of doctor is Dr. Mark C. Walker I?
Dr. Mark C. Walker I is a psychiatrist in Ocala, Florida. The primary specialty in the NPI Registry is Psychiatry Physician (taxonomy code 2084P0800X).
Where does Dr. Mark C. Walker I practice?
Dr. Walker practices at 3235 Sw 34th St, Ocala, FL 34474. Dr. Walker's primary practice is Harmony United Florida in Ocala, Florida. Dmand AI also links Dr. Walker to 1 group practice or clinic.
What is Dr. Mark C. Walker I's office phone number?
The practice phone on file for Dr. Walker is (352) 431-3940.
What is Dr. Mark C. Walker I's medical license number?
Dr. Walker holds Florida license ME108732.
What medical group is Dr. Mark C. Walker I part of?
Dr. Walker is linked to Harm Reduction Center.
Does Dr. Mark C. Walker I accept Medicare?
Yes. CMS data shows Dr. Walker billed Medicare for 462 services in 2021, and Dr. Walker accepts Medicare assignment.
Does Dr. Mark C. Walker I offer telehealth?
Yes. The CMS Doctors and Clinicians file lists Dr. Walker as offering telehealth services.
What services does Dr. Mark C. Walker I bill to Medicare?
In 2021, Dr. Walker's most billed Medicare services were psychiatric service (90833), office visit, established patient (99214) and office visit, new patient (99204).
Where did Dr. Mark C. Walker I go to medical school?
Dr. Walker graduated from American University of the Caribbean School of Medicine in 1990.
Show 4 more questionsShow fewer questions
What drugs does Dr. Mark C. Walker I prescribe most?
In 2024 Medicare Part D data, Dr. Walker's most prescribed drugs by claims were Duloxetine HCl, Alprazolam and Clonazepam.
Has Dr. Mark C. Walker I received payments from drug or device companies?
CMS Open Payments shows $957 in general payments to Dr. Walker from 15 companies from 2016 to 2021. The largest total came from Otsuka America Pharmaceutical, Inc.
How long has Dr. Mark C. Walker I been practicing?
Dr. Walker graduated from medical school in 1990, 36 years ago.
What insurance does Dr. Mark C. Walker I accept?
Dr. Walker is in network with 6 carriers, including Aetna, United Healthcare and CMS Medicare. PPO plans come from the most carriers, 4. Check the plan with the practice before a visit.
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