  This proceeding reports the ATLAS results of measuring vector boson
production in $pp$ and $p$+Pb collisions at the center-of-mass energy of
5.02~TeV per nucleon. $Z$ boson bosons are reconstructed via leptonic decays
and results are presented as a function of $Z$-boson rapidity. $W$ boson bosons
are identified by measuring leptons coming from $W$ boson decays and the
results are presented as a function of lepton pseudorapidity. In $pp$
collisions $Z$ boson boson cross section in $|y_{Z}|<2.5$ is 590$\pm$9
(stat.)$\pm$12 (syst.)$\pm$32 (lumi.) pb. In $p$+Pb system kinematic
distributions of $W$ boson and $Z$ boson bosons are compared to models based on
NLO and NNLO QCD calculations using different PDF sets. Using PDF modification
shows better agreement of the model and the data. Measurements done in
different centrality intervals show that the PDF modification in $p$+Pb may
have centrality dependence.
