Six cases demonstrating the utility of pulsed Doppler sonography as an aid in avoiding complications of aspiration and biopsy are presented. Duplex sonography combined with ultrasound needle guidance was helpful in identifying the vascular nature of masses in 3 cases and positively identifying and avoiding vascular structures within the needle path in 3 cases. The selective use of duplex sonography prior to aspiration biopsy provides information that should serve to minimize further the risks of hemorrhage associated with modern biopsy techniques.