  We take into account the constraints from the observed extragalactic
gamma-ray background to estimate the maximum duty cycle allowed for a selected
sample of WMAP Blazars, in order to be detectable by AGILE and GLAST gamma-ray
experiments. For the nominal sensitivity values of both instruments, we
identify a subset of sources which can in principle be detectable also in a
steady state without over-predicting the extragalactic background. This work is
based on the results of a recently derived Blazar radio LogN-LogS obtained by
combining several multi-frequency surveys.
