Our pediatricians are Fellows of the American Academy of Pediatrics.  Pediatricans who maintain their FAAP designation have obtained board certification in pediatrics and made an ongoing commitment to lifelong learning and advocacy for children.

Erin O'Brien, MD, FAAP
Erin O'Brien, MD, FAAP

Dr. O'Brien was born in Chicago and attended Loyola University where she earned a B.A. in sociology.  She attended Rush Medical College and received her M.D. in 2000.  She completed her pediatric residency in 2003 at Rush Presbyterian St. Luke's Medical Center in Chicago.

Jason Tjaden, MD, FAAP
Jason Tjaden, MD, FAAP

Dr. Tjaden was raised in downstate Vandalia and received his B.S. with honors in biochemistry from the University of Illinois Urbana-Champaign.  He attended medical school at the University of Illinois Peoria and completed his residency in pediatrics at Cincinnati Children's Hospital Medical Center where he received an Adolescent Medicine Award in recognition of his achievements in adolescent medicine.

P: 847-658-6065

F: 847-658-6136


301 N Randall Rd

Lake in the Hills, IL 60156

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Masks will be required in our office should McHenry County COVID community levels become HIGH





Open Letter to Parents
VPS 1.1.16.pdf
Adobe Acrobat Document 136.6 KB


Required Vaccines for IL Schools
IL immunization reqirements 2021.pdf
Adobe Acrobat Document 171.3 KB