The concentration of radiative silicon centres in polycrystalline diamond films grown on silicon wafers was tentatively measured by their laser-induced luminescence (PL) at 1.681 eV. The total area under the PL line at room temperature is proportional to the amount of radiative Si point-defects in the volume excited by the laser beam. This amount was normalized to the area (expressed with the same arbitrary unit) under the diamond Raman line at 1332 cm -1 obtained simultaneously on the same set-up and compared to the absolute concentration determined by SIMS experiments. A linear relationship was obtained between the normalized PL area and the averaged SIMS values. Room temperature slope values (α laser ) of the linear relationship were obtained for the following laser lines: 632.8 nm, α 633 = 7.8 E + 15, 514.5 nm, α 514 = 2.5 E + 16 and for 488 nm, α 488 = 5.5 E + 16 at/cm 3 . SIMS profiles obtained in the different layers indicate that the distribution of silicon in the layers is a consequence of thermally activated diffusion from the silicon substrate during film growth.