At least 1.5 billion in the world and over 100 million Russians live in iodine-deficiency areas. The sequelae of this condition are well known. The paper discusses the properties of the iodinated lactoprotein caseoiodine designed by the MRRC researchers and its capacities and advantages for using in the prevention of iodine deficiency. The assimilation of iodine from caseoiodine corresponds to the body's status: it significantly accumulates more frequently in the thyroid in dietary iodine deficiency (Group 1) and to a lesser degree in adequate dietary iodine intake (Group 2) and, by hour 72, amounts to 36.3 and 31.4% of the ingested amount, respectively (P < 0.05). The findings are in agreement with the data available in the literature on the involvement of hepatic enzymes in regulating the metabolism of iodine during its intake in the protein (casein)-bound form and in increasing its fecal excretion (up to 40% in Group 2) whereas 95% iodine excrete with urine when inorganic iodine is consumed.