The pyrene movement in a lipid bilayer has been shown to occur not only in the lateral but also transmembrane direction. Within the excited state lifetime the pyrene monomer elevates from the depth to the polar regions of the membrane and emits a luminescence photon. The excimer does not exhibit any marked transmembrane movement while luminescing from the hydrophobic regions. The luminescence quenching efficiency of monomers and excimers depends on the depth of quencher penetration into the membrane. In the lipid bilayer the pyrene luminescence is strongly quenched by molecular oxygen. The pyrene binding to membrane proteins protects it from quenching. A conclusion has been made that the carrying out estimations of membrane viscosity from pyrene luminescence require considerable correction.