This paper presents estimates of ionizing radiations in the Earth's atmosphere obtained by calculating primary cosmic ration passing through it. The contribution of protons with energies of up to 200 MeV and neutrons with energies of 0.1 to 100 MeV to the equivalent dose rate produced by fluxes of ionizing radiations of cosmic origin amounts to 90%. The contribution of electrons and gamma-rays is one order of magnitude smaller and the contribution of muons and pions is negligibly small. The paper gives data about the altitude and latitude distribution of equivalent dose rates generated by fluxes of galactic and solar cosmic rays. The dose rate level reaches its maximum at altitudes of about 20 km and in the regions situated to the North of 67 degrees N. 1.