Results on hard diffraction from CDF are reviewed with emphasis
on the determination of the diffractive structure function of the
(anti)proton from single diffractive and double Pomeron exchange dijet
production. Comparison of the diffractive dijet results with predictions
based on diffractive deep inelastic scattering at HERA shows a breakdown of
conventional QCD factorization. A similar breakdown is observed within the
CDF results in comparing the structure functions obtained from single
diffraction and double Pomeron exchange.