Pomona Pediatrics provides care to infants, children, adolescents, and young adults up to age 18.
Our Doctors
Pomona Pediatrics has been caring for families in the Pomona Valley since 1982, and the depth of this team reflects it. Dr. Sandra Hollenberg, one of our founding physicians, has been here since day one. Dr. Carrie Knoll, who joined in 1998, is a Sleep Medicine Specialist who sees children at the Pomona Valley Hospital Sleep Disorder Center.
Today, our seven board-certified pediatricians are all Fellows of the American Academy of Pediatrics, each bringing their own specialty and decades of experience to a practice that has earned the trust of generation after generation of Pomona families. This is what four-plus decades of doing it right looks like.
Sandra Hollenberg, MD
Dr. Sandra Hollenberg is a board-certified pediatrician at Pomona Pediatrics since 1982, known for her commitment to both family-centered care and keeping the practice at the forefront of electronic medical charting.
Ericka Hong, MD
A Pomona Pediatrics physician since 2006, Dr. Ericka Hong is a board-certified, AAP-affiliated pediatrician dedicated to the health and well-being of infants, children, and teens.
Carrie Knoll, MD
Dr. Carrie Knoll is a board-certified pediatrician at Pomona Pediatrics, providing family-centered care for infants, children, and teens since 1998 as a member of the American Academy of Pediatrics.
Toya Tillis, MD
Dr. Toya Tillis has been delivering comprehensive, family-centered pediatric care at Pomona Pediatrics since 2011, and is a board-certified member of the American Academy of Pediatrics.
James Warren, MD
A loved Pomona Pediatrics physician since 2001, Dr. James Warren is a board-certified, AAP-affiliated pediatrician dedicated to the health and well-being of infants, children, and teens.
Diana Yu, DO
Dr. Diana Yu has been delivering comprehensive, family-centered pediatric care at Pomona Pediatrics since 2021, and is a board-certified member of the American Academy of Pediatrics.
Patricia F. Villegas, DO
“As a mother of two children myself, I bring an empathetic and attentive approach to pediatric care, supporting families throughout their journey from infancy to young adulthood.”
