The results of scintigraphic and cytological investigations in 548 patients with goiter are presented: In 402 goiters 470 nodes were detected, 385 of which were scintigraphically "cold". 276 solitary nodules were found, 109 in cases of multinodular goiter. Solitary nodules were preferentially located in the right lobe. The cytological diagnosis was confirmed histologically in 88 cases. Out of 24 malignant tumors, 21 were diagnosed correctly by means of cytology. The positive smears and the histological findings were in agreement in 14 of 15 cases. The accuracy of cytological diagnosis in the detection of thyroid malignancies was 87.5%. 12.5% of the smears were false negatives, 1.6% false positives and 10.9% false suspicious. The relative high percentage of false suspicious smears is caused by difficulties in cytologic differentiation of thyroid lesions due to microfollicular structures which are usually only classified as "follicular neoplasia". This cytologic term necessitates an obligatory histologic examination since cytology does not allow to differentiate between follicular adenomas and carcinomas. 5.5% of the histologically ascertained cold nodules were malignant, in 19% of the cases with cold nodes thyroid punction revealed cystic lesions.