Structure functions and parton densities at HERA

A review of HERA I structure functions is presented. The rise of F2 at low ξ is discussed, and the first direct measurement of FL by the ZEUS collaboration is introduced, to complement the measurements previously made by H1. Charged and neutral current deep inelastic scattering cross sections are then reviewed, including the first polarised charged current deep inelastic scattering data from HERA II. A brief review of recent NLO QCD fits to HERA I data is then presented.