Percutaneous puncture for cytologic study was performed in 136 patients with nodular goiter. All patients were operated on and correlation of cytologic and histologic findings was obtained. Echographic study revealed a solid aspect in 72%, cystic aspect in 10% and mixed in 18%. The cytologic findings were classified as: benign--hyperplasia--, chronic thyroiditis, follicular neoplasm (adenoma and carcinoma), oxyphilic neoplasm (adenoma and carcinoma), papillary cancer, medullary cancer, anaplastic cancer and insufficient material. Surgery revealed cancer in 36 patients (26.5%). There were 3 false positives for cancer in the cytologic study. Percutaneous cytology was able to detect 88% of patients with cancer and 83% of patients with neoplasms. False negatives for cancer (n = 5) were due to insufficient sample (2), topographic error (2) and cytology error (1). No follicular cells were obtained in 13 patients with cystic follicular adenoma and the diagnosis was missed. Surgery confirmed that 24 of 25 patients with cystic aspect on echography had a basic underlying lesion. Thus, percutaneous cytology of the thyroid is useful in the evaluation of patients with cold nodules. Main limitations of the technique are found in patients with cystic lesions and follicular neoplasms.