SrBi2(Ta,Nb)2O9ferroelectric thin film capacitors with RuO2electrodes were prepared for the first time by a full chemical route. Stable sols of SrBi2(Ta,Nb)2O9precursors were obtained from mixtures of niobium (tantalum) ethoxide, bismuth and strontium 2-ethylhexanoates. Ruthenium dioxide precursors was prepared by dissolving an aqueous solution of ruthenium nitrosylnitrate into 2-methoxyethanol. Capacitors were fabricated by sequential spin coating the precursors on silicon wafers according to the sequence Si/RuO2/SrBi2(Ta,Nb)2O9/RuO2. Fully crystallized crack-free materials were obtained by annealing at 700°C for 2 h. Hysteresis loops (3–10 V) are similar to those observed using platinum electrodes.