The frequency of indication for surgical resection of goitre was retrospectively analysed for 2100 thyroid examinations. During 1974/75 (group I) only scintigraphy was available in addition to clinical examination; in 1979/80 (group II) cytological criteria were added, and in 1983/84 (group III) ultrasound findings were available as well. There were 700 patients in each group. The proportion of scintigraphically negative nodules was largely the same in the three groups (I and II: 21%; III: 22%). Indication for operation was less common after the introduction of ultrasound (I: 56%; II: 55%; III: 44% of patients with scintigraphically cold nodules). In particular, there was a decrease in the proportion of those nodules not definitely considered benign which would have required histological diagnosis (I: 32%; II: 18%; III: 8%). The results underline the special place of small-needle biopsy and, especially, ultrasound examination of the thyroid, in addition to clinical and scintigraphic findings, in providing the indication for and planning of operative nodular goitre resection.