The role of nitrates in goitre genesis has been discussed for a long time. In the present report a comparative analysis is made of results obtained in villages with nitrate pollution of the drinking water. In two pairs of villages children aged between 3 and 14 were included, whose thyroid status was investigated by a clinical examination. The study was carried out in 2 stages – in 1995 and 1998. In this period the goitre incidence was significantly reduced in both sexes. Both investigations showed a higher relative risk of goitre in children exposed to water pollution by nitrates. In the first, as well as in the second examination, goitre was diffuse. We concluded that nitrate pollution of drinking water undoubtedly participated in goitre genesis. We did not underestimate the strumigenic effect of nitrates in the diet as they were not the object of our investigation and which, accordings to WHO experts, have a less strumigenic effect. After the first investigation we recommended a higher antistrumin dose as prophylaxis. That is why we conclude that the considerable goitre reduction in the second investigation was the positive result of the doubled antistrumin prophylaxis during the period between the two investigations.

        Key words: nitrate, drinking water, goitre