Forty-seven patients with thyroid nodules (13 papillary carcinomas, 14 adenomas, and 20 adenomatous goiters) underwent color Doppler sonography with a 7.5 MHz transducer. Perinodular or intranodular color flow signals were depicted in 10 of 13 papillary carcinomas, in 10 of 14 follicular adenomas, and in 14 of 20 adenomatous goiters. No correlation existed between the presence of color signals and pathology, whereas the detection rate of color signals had a dependence on the size of the lesions. No specific flow pattern for malignancy could be found. Color Doppler sonography would not improve the ability to differentiate benign from malignant nodules significantly.