Abstract
The production of W/Z-bosons in association with jets is an important test of perturbative QCD predictions and also yields information about the parton distribution functions of the proton. We present fits to determine PDFs using inclusive W/Z-boson and W/Z+jets measurements from the ATLAS experiment at the LHC. The ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. An improved determination of the sea-quark densities at high Bjorken-x is seen, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x<0.02 found by previous ATLAS analyses.