Implications of the e+e- measurements at LEP, in particular the determination of the number of neutrino flavors with mν ≲MZ/2, on big bang nucleosynthesis and on dark matter are discussed. For the early Universe, the LEP measurements fix Nν = 3. This together with recent measurements of the neutron half-life and new observations of 4He and 7Li determine the baryon-to-photon ratio η = 3 × 10-10 implying that baryons provide only 1-8% of the closure density. In addition the determination that Nν ≤ 3.14 (95% C.L.) indicates that certain dark matter candidates such as Dirac and Majorana neutrinos are excluded. The supersymmetric parameter space is somewhat restricted but still easily allows for candidates supplying the missing mass in the Universe.