This paper reports the synthesis, structure and the conductivity study of the new monovalent phosphates of the formula Na2MTi(PO4)(3), M = Fe or Cr. The structures of these compounds have been refined from X-ray powder diffraction by the Rietveld method. Their reflections are indexed in the cubic system with langbeinite-type structure in the P2(1)3 space group. This structure can be best described in terms of [M2P3O18] structural units composed of two MO6 octahedra linked to each other through three PO4 tetrahedra. Curie-type behaviour is observed in the magnetic susceptibility, which confirms the trivalent state of M metals and suggest no magnetic interactions. The electrical behaviour of these phases show that the activation energies are relatively high and they could be related to the previous structural analysis