Iodine-deficiency disorders are a major problem of public health in Morocco. To mitigate this deficiency, the iodination of all the salt intended for human consumption in a proportion of 80 +/- 10 mg/kg of salt has become obligatory since a decree published in 1995. We estimated that this rate of iodized salt issued risked inducing an iodine excess in the population. To check this hypothesis, we provided 7 families made up of 28 subjects, who at the start were consuming a non-iodized salt, with the decreed, iodized salt and we followed the evolution of their urinary iodine excretion over a period of 3 weeks. The mean values of urinary iodine excretion of the 28 subjects were 12.8 micrograms/dl before use of iodized salt and 26.8, 35.5 and 63.2 micrograms/dl, respectively, after 7, 14 and 21 days from the introduction of iodized salt into their diet. After 21 days of the use of iodized salt, 84.6 per cent of the subjects had an iodine excess. We conclude that prolonged use of this iodized salt exposes the population to the risk of thyroid disorders.