A co-precipitation synthesis of precursors to bismuth-containing ceramic superconducting materials is disclosed in which bismuth and at least one other approrpiate metal are dissolved in a non-aqueous acidic solvent, which are then recovered as a homogeneous dry powder. The mixed metal salts are co-precipitated from aqueous solution in the form of the corresponding homogeneous hydroxycarbonate precursor mixture by reaction with either sodium carbonate or potassium carbonate. The homogeneous precursor may be then converted to the BiCuSrCuO.sub.x ceramic by calcining the mixed hydroxycarbonate to a powder, compressing said powder into a green compact, sintering said green compact at a temperature of at least 750.degree. C., and cooling the ceramic material so produced at a controlled rate, preferably about 50.degree. C./minute.