  Blazars are a small fraction of all extragalactic sources but, unlike other
objects, they are strong emitters across the entire electromagnetic spectrum.
Recent data in the microwave region of the electromagnetic spectrum have become
available to allow for systematic studies of blazars over large cosmological
volumes. This frequency band is indeed particularly suited for the selection of
blazars since at these frequencies the contamination from radio extended
components with steep spectra is no longer present and the emission from the
accretion process is negligible. During the first 3 months of scientific
operations Fermi-LAT detected 106 bright, high-galactic latitude (| b |> 10
deg) AGNs with high significance. In this study we investigate the possible
relations between the microwave and the gamma-ray emissions for Fermi-LAT
detected AGNs belonging to WMAP 5th year bright source catalog.
