  We present a new one-dimensional calculation of low and intermediate energy
atmospheric muon and neutrino fluxes, using up-to-date data on primary cosmic
rays and hadronic interactions. The existing agreement between calculated muon
fluxes and the data of the CAPRICE 94 muon experiment provides an evidence in
favor of the validity of our description of hadronic interactions and shower
development. This also supports our neutrino fluxes which are essentially lower
than those used for the standard analyses of the sub-GeV and multi-GeV neutrino
induced events in underground detectors.
