PURPOSE Assessment of the functional diagnostic value of Doppler sonographic or sonographic parameters, especially of the peak flow velocity in the inferior thyroid artery in patients with newly manifest autoimmunothyroiditis. MATERIAL AND METHOD Morphological and Doppler sonographic measurements were done at the inferior thyroid artery on 69 patients suffering from newly manifest Graves' disease or Hashimoto's thyroiditis, as well as on a control group of 18 subjects. The measured data were correlated with thyroid hormone levels and with quantitative scintiscanning. RESULTS A linear functional correlation was found between the peak flow velocities in the inferior thyroid artery and the fT3 or fT4 level. If the peak flow velocities were greater than 1.2 m/s, hyperthyroid metabolism prevailed, whereas at velocities below 0.3 m/s latent hypothyroidism was present. CONCLUSION These results show that Doppler sonography of the inferior thyroid artery can supply pointers (capable of being recorded) to the state of functioning of the thyroid even before knowing the laboratory parameters.