Thyroid nodules less than one centimetre in diameter raise the problem of differential diagnosis between a benign formation and cancer. The question is of major importance since nodules can be found in approximately one-half of the population. Fine-Needle Aspiration should be performed if the nodule is palpable. When cytologic diagnosis is not possible, the discovery of a small nodule in the thyroid gland is not an alarming finding in itself as long as the absence of involvement of the satellite nodes or other associated symptomatology is confirmed. We have operated 102 patients with differentiated microcancers with no metastasis other than local node involvement. All have been seen regularly for annual check-ups and only 2 have developed pulmonary and bone metastases with a fatal outcome. The prognosis of microcancers is thus much better than that of larger tumours since in a series of more than 500 cancers we have observed 5 and 10 year survivals of 96 and 92% respectively. In addition, unlike large tumours, small cancers of the thyroid are not anaplastic. We thus propose annual surveillance for patients with uncomplicated small nodules of the thyroid gland less than 2 cm in diameter. Complementary examinations should be limited. Conversely we operate the nodules exceeding 2 cm in order to reduce the frequency and severity of thyroid cancer. It should be recalled that neither clinical manifestations, echography, thyroglobulin, needle biopsy, nor any other diagnostic tool has been shown to have sufficient prognostic power to predict the benign nature of a voluminous nodule.