Proton structure and PDFs at HERA

The neutral and charged current deep-inelastic ep scattering cross sections are measured in the H1 and ZEUS experiments at HERA (1992-2007), with an electron beam energy of 27.6 GeV and proton beam energies of 920, 820, 575 and 460 GeV. In the second phase of the HERA operation (2003-2007) the lepton beam was longitudinally polarised. The data are used to determine the proton structure functions and are analysed in the QCD framework to obtain the parton distribution functions of the proton