The iodine concentration was determined in 89 thyroid tissue samples of post-mortem examination material of thyroid healthy persons in dependency to the age. Before the 22nd week little iodine is stored in the fetal thyroid gland (median and range: 24 micrograms/g wet weight [0 to 27 micrograms/g]). From the 23rd week on the concentration is significantly higher (p = 0.004). There is a further increase of iodine concentration in the first 6 months of life, with a median concentration of 171 micrograms/g (75 to 808 micrograms/g). With a median of 599 micrograms/g (464 to 699 micrograms/g) the iodine concentration in the second year of life is comparable with that of adults (640 micrograms/g [218 to 2772 micrograms/g]). From the 60th year of life the median concentration is 462 micrograms/g (155 to 2100 micrograms/g), but this decrease is not statistically significant. Additionally the iodine concentration was determined in 7 topographically defined regions of 28 thyroid glands. The median iodine concentration did not differ in the 7 regions, but the iodine content in one and the same thyroid gland differed from region to region. Therefore in the healthy thyroid gland no regions exist, which have generally stored less iodine than others. However, no conclusion can be drawn from the iodine concentration of one biopsy to the whole iodine concentration of the organ.