The twins, from Norton, near Gloucester, will both go to Cambridge University to study veterinary science after being awarded five A grades each.
The identical twins received straight As in exactly the same subjects: maths, biology, physics, chemistry and general studies. Lydia said yesterday she was relieved - both sisters had always been fiercely competitive as they grew up.
"I'm absolutely amazed we got the same results but I'm so relieved," she said. "Otherwise one of us would have had bragging rights over the other"
Caroline said she and her sister both loved science and chose the same subjects at the High School for Girls, a state grammar school in Gloucester. She added: "It's very strange that we both got the same results. I can't quite believe it."
The sisters will have to get used to spending time apart when they get to Cambridge. Lydia will be studying at Girton College and Caroline has accepted a place at New Hall. Caroline said: "Part of the attraction of going to Cambridge was that we could be together and see each other."