2026 NPPES data Adult Medicine Physician NPI 1255462578 MD
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Roberto Diaz, MD

Adult Medicine Physician in Chicago, Illinois.

This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 2,481 in Adult Medicine Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.

Federal data, no proprietary rating. We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Roberto Diaz, MD is a Adult Medicine Physician in Chicago, Illinois, listed in the federal CMS National Provider Identifier registry.

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.

Board-eligible specialty (heuristic, not verified)

Roberto Diaz, MD practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Roberto Diaz, MD?

Quality data not reported

NPI registry status

Active

Issued 03/08/2007

NPI 1255462578

Primary specialty

Adult Medicine Physician

Niche

2,481 US NPIs in this specialty

Specialty distribution in Illinois

How Adult Medicine Physician compares to other specialties among Illinois providers

Illinois providers
Clinical Social Worker - 5.2%Clinical Social Worker5.2%Physical Therapist - 5%Physical Therapist5%Mental Health Counselor - 4.5%Mental Health Counselor4.5%Speech-Language Pathologist - 4.2%Speech-Language Pathologist4.2%Student in an Organized Health Care Education/Training Program - 4.2%Student in an Organized Health Care Education/Training Program4.2%Pharmacist - 4.1%Pharmacist4.1%Adult Medicine Physician - 0%Adult Medicine Physician0%
Largest specialties in Illinois (% of in-state providers)

Board certification

Not published by CMS

CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Adult Medicine Physician. Verify directly:

How MIPS and board certification work

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

Roberto Diaz, MD appears in the CMS NPPES registry as a Adult Medicine Physician provider holding MD credentials at 1805 S ASHLAND AVE, Chicago, IL, 60608, with a listed phone of (312) 421-7010. NPI 1255462578 was issued on 03/08/2007.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal, many Adult Medicine Physician providers operate outside Part D entirely.

Adult Medicine Physician is a narrow specialty nationwide, with 2,481 enrolled providers across 52 states and an average of 2,807 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.

Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist, always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

1805 S ASHLAND AVE
Chicago, IL 60608

Provider Details

NPI 1255462578
Specialty Adult Medicine Physician
Credentials MD
Gender Male
NPI Issued 03/08/2007

License & disciplinary context - Illinois IDFPR 2023 annual report

Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~42K Illinois medical licensees in 2023 - they are NOT specific to Roberto Diaz, MD. To verify Roberto Diaz, MD's current license status, search the IDFPR public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

106
Total board actions, Illinois 2023
Across 103 cases
2.52
Actions per 1,000 licensees
Illinois statewide rate
probation
Most common action type
38 cases

IDFPR publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the Illinois disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Adult Medicine Physician Overview

How Roberto Diaz, MD fits within the Adult Medicine Physician landscape nationally.

2,481
Adult Medicine Physician Providers in US
52
States with Adult Medicine Physician
2,807
Avg Claims per Provider

Nearby Adult Medicine Physician Providers in Illinois

Other clinicians with the same primary specialty enrolled in Illinois, drawn from the same CMS NPPES roster as Diaz.

Compare Adult Medicine Physician nationally: see state-by-state distribution →

Before you book an appointment

Use this federal record as your verification checklist, not as a recommendation.

  • Confirm the NPI record is current in the official CMS registry, providers update their own NPPES details, and moves can lag. Verify this NPI
  • Check the active license and any disciplinary history with the Illinois medical board, federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Adult Medicine Physician peer on Medicare volume and prescribing patterns. Compare providers

Medicare Part D and MIPS figures describe practice patterns in federal programs only, they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.

Frequently Asked Questions

What is Roberto Diaz, MD's specialty?
Roberto Diaz, MD specializes in Adult Medicine Physician and practices in Chicago, Illinois. Credentials: MD.
Where is Roberto Diaz, MD located?
Roberto Diaz, MD is located at 1805 S ASHLAND AVE, Chicago, IL, 60608. Phone: (312) 421-7010.
What is Roberto Diaz, MD's NPI number?
Roberto Diaz, MD's National Provider Identifier (NPI) is 1255462578, issued on 03/08/2007.
How many Adult Medicine Physician providers are there in the US?
There are 2,481 Adult Medicine Physician providers across 52 states in the US. The average Adult Medicine Physician provider writes 2,807 Medicare Part D claims per year.
Does Roberto Diaz, MD accept Medicare?
Roberto Diaz, MD appears in CMS Medicare data. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Roberto Diaz, MD's credentials?
Roberto Diaz, MD's NPI is 1255462578 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

View source datasets and methodology notes
Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology

Compiled from official public sources by the PlainDoctor editorial team.