We report the first measurement of the absolute branching fraction for Λ+c→Λe+νe. This measurement is based on 567 pb−1 of e+e− annihilation data produced at s√=4.599 GeV, which is just above the Λ+cΛ¯−c threshold. The data were collected with the BESIII detector at the BEPCII storage rings. The branching fraction is determined to be B(Λ+c→Λe+νe)=[3.63±0.38(stat)±0.20(syst)]%, representing a significant improvement in precision over the current indirect determination. As the branching fraction for Λ+c→Λe+νe is the benchmark for those of other Λ+c semileptonic channels, our result provides a unique test of different theoretical models, which is the most stringent to date.