Аннотация:The branching fraction of the rare decay Λb0→Λ(1520)μ+μ- is measured for the first time, in the squared dimuon mass intervals q2, excluding the J/ψ and ψ(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb-1. The result in the highest q2 interval, q2>15.0 GeV2/c4, where theoretical predictions have the smallest model dependence, agrees with the predictions.