Until 2000 Denmark was iodine deficient with moderate deficiency in the western part and mild deficiency in the eastern part. The occurrence of goitre and autonomous hyperthyroidism was high, and pregnancy was associated with a reduction in thyroid function. After cautious mandatory iodization of household salt and salt used for bread production, the iodine intake in Denmark is now low normal. The DanThyr monitoring has shown a transient increase in hyperthyroidism followed by a decrease, and goitre is becoming less common. Hypothyroidism has become more common, and this has to be followed.