A spectrophotometric method is proposed for the determination of iodine in urine samples. Destruction of the organic matter of urine by alkaline ashing with KOH is carried out prior to determination of iodine by the iodine-starch method. The influence of components of urine, as interferents, was discussed. The iodine contents of the urine samples collected from adults from Kayseri (Turkey) were determined by using the proposed method. The method was also applied for the determination of iodine in drinking water samples. The relative standard deviations of the iodine determinations were less than 10%. The detection limit of the proposed method was 2.3 mu g l(-1).