Two-point Functions at Two Loops in Three Flavour Chiral Perturbation Theory

The vector and axial-vector two-point functions are calculated to next-to-next-to-leading order in Chiral Perturbation Theory for three light flavours. We also obtain expressions at the same order for the masses, $m_\pi^2$, $m_K^2$ and $m_\eta^2$, and the decay constants, $F_\pi$, $F_K$ and $F_\eta$. We present some numerical results after a simple resonance estimate of some of the new ${\cal O}(p^6)$ constants.