Abstract: A new method for the determination of iodide and organiciodine compounds using a gold-coated quartz piezoelectric crystal is developed. Iodine is extracted into the carbon tetrachloride phase after decompositon of thesample by oxygen flask combustion method. The frequency of the crystal is decreased when iodine is adsorbed on the gold electrode of the crystal from the carbon tetrachloride solution. The only interference is found from bromine. The linear range is 1 × 10^-7～3 × 10^-5M. Reversibility of the detector is achieved by immersion in ammonia water for 5～10 min. The method is suitable for determining iodine content in organic-iodine compounds and for determination of organic-iodine compounds in aqueous solutions, urine and blood.