Between February, 1986, and September, 1988, 404 biopsies have been done, under ultrasound guidance, with a cutting needle fired by a spring-loaded device. Sensitivity for a diagnosis of malignancy was 92.7%; overall accuracy was 94.1%; the predictive value of a positive result was 100% and the complication rate was low. An exact diagnosis could be made from histological examination of the specimen obtained from 98% of positive tumour biopsies. This technique is a simple and safe way to obtain specimens for accurate histological diagnosis.