SnO2 sol-gel derived thin films doped simultaneously with Pt and Sb are obtained and reported for the first time. The Sn sources were tin(IV) ethoxide or tin(II) ethylhexanoate, while hexachloroplatinic acid (H2PtCl6) and antimony chloride (SbCl3) were used as platinum and antimony sources, respectively. Transparent, crack-free layers, deposited on silicon or porous silicon (PS) substrates were obtained with antimony doping in the range (0-2)% M, while the platinum addition was limited to maximum 1% M, due to the strong acidic character of the Pt and Sb precursors. Ternary sol (Pt:Sb:SnO2) stability was analysed by viscosity studies while the surface roughness of the doped SnO2 layers on both types of substrates was investigated by atomic force microscopy (AFM) measurements. Rutherford Backscattering spectra (RBS) analysis proved that pores of PS substrates had been filled as a result of multiple spin-casting processes.