A method for the determination of total iodine in biological material has been developed. The method combines alkaline ashing with a selective and sensitive column-switching ion-pair HPLC technique. The ashing procedure which converts the organically bound iodine to iodide is miniaturised and requires only about 100 mg of sample. The first column of the column-switching system is polymer based and can therefore withstand the alkaline pH obtained after ashing. On the analytical column the iodide is separated as an ion-pair with tetrabutyl ammonium hydrogensulphate. The method has been applied to samples from whole blood, urine, liver, lung, carcass, and a sample throughput of at least 50 samples per day can be achieved. Validation studies by spiking experiments showed the precision to be better than 10% R.S.D. for all matrices with recoveries in the range 87-97%. The method has been applied for samples with an iodine content in the range 0.07-1060 microg/g.