Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Dr. John Mark Leib, DMD

Individual provider Dentist · NPI 1376604678

Dr. John Mark Leib, DMD is a Dentist in O Fallon, Illinois. Licensed in Illinois. Registered with an NPI since 2006.

Licensed in
IL
In the registry since
2006
Specialties on file
2
What do these letters mean?
DMD — Doctor of Dental Medicine
A dentist. Identical training and licensing to a DDS.

See every abbreviation used in this directory →

Practice location Address checks out

741 W State St Ste 3
O Fallon, IL 62269-1971
Phone: (618) 628-1800
Fax: (618) 628-3406
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Dentist (primary) Taxonomy 122300000X (IL)
Oral and Maxillofacial Surgery (Dentist) Taxonomy 1223S0112X (IL)

Record details

NPI number1376604678
Entity typeIndividual (Type 1)
GenderMale
Credentials DMD
Sole proprietorNo
NPI enumeratedDecember 12, 2006
Last updated in NPPESSeptember 11, 2025
Mailing address741 W State St, Suite 3, O Fallon, IL 62269-1971

Other providers in O Fallon