An analytical investigation of the onset of convection in a horizontal porous saturated by a nanofluid, and subjected to g-gitter (or vertical vibration) is presented. The Darcy model is used for the porous layer and a linear stability analysis is used to determine the convection threshold in terms of the key parameters for the nanofluid in a homogenous porous medium. The results are presented for the special case when the porosity to heat capacity ratio is unity. The critical Rayleigh number and wavenumber is presented in terms of the nanofluid parameter. (C) 2017 Published by Elsevier Ltd.