Dr. Ooi graduated from the University of Singapore and pursued his training in Obstetrics & Gynaecology at the University Hospital in Kuala Lumpur and the University College Hospital in London. He obtained his Membership from the Royal College of Obstetricians & Gynaecologists in 1976 and his Fellowship in 1990.

After completing his postgraduate examination, he served in one of the hospitals in England before returning to join Gleneagles Medical Centre in 1977.