Theory has shown that in young and compact extragalactic radio sources lobes and jets can produce gamma- ray flux, via Compton scattering of different seed photons, to levels potentially detectable by Fermi LAT. Being contributed only by the non-thermal emission, the gamma-ray band is important to ascertain the origin of the whole high-energy (X- to gamma-ray) output in this class of sources. This is a crucial aspect for our understanding of the radio sources’ evolution and the feedback mechanism with the host galaxy during the initial stage of evolution. We report the results of our investigation on the gamma-ray emission of a sample of young quasars and radio galaxies, already observed in the X-rays, using >3 yrs of Fermi LAT data. LAT data are used to test theoretical models predicting beamed and unbeamed high energy emission in such objects.