Results are presented on the production of Z \rightarrow \mu \mu and W \rightarrow \mu \nu in the forward region at LHCb. The analysis is based on an integrated luminosity of 16.5 ±1.7 pb-1. The production cross-section for Z with muons in the pseudorapidity range 2<\eta \mu <4.5 and 81 Z <101 GeV is 74±2±3±7 pb and is also measured differentially in rapidity of the Z. The total cross-section for W production is \sigma W+(2<\eta <4.5) = 1007±48±101 pb and \sigma W-(2<\eta <4.5) = 680±40±68 pb in the lepton pseudorapidity range 2 < \eta < 4.5. The charge asymmetry is measured as a function of the lepton pseudorapidity. All results are in agreement with next to leading order perturbative QCD predictions.