This study was undertaken to investigate the repeatability (intraobserver variability) of power Doppler sonography in assessment of cervical lymph nodes. Power Doppler sonography was performed twice in 20 healthy subjects to evaluate the repeatability of measurement of size, blood flow velocity (peak systolic velocity, PSV, and end diastolic velocity, EDV) and vascular resistance (resistance index, RI, and pulsatility index, PI) of cervical nodes. A total of 70 power Doppler sonograms were reviewed to evaluate the repeatability of assessment of vascular pattern, degree of vascularity and displacement of vessels of cervical lymphadenopathy. In the 20 subjects, 139 normal cervical nodes were detected in the first scan and they were re-scanned in the second scan. One node was detected in the second scan, but not in the first scan. Of the total, 50 cervical nodes showed arterial flow in both scans, and blood flow velocity and vascularity resistance were measured. The mean value of PSV, EDV, RI and PI have a higher repeatability than their highest and lowest values. There is a high repeatability in the measurement of maximum transverse diameter (97%), mean PSV (95%), mean EDV (96%), mean RI (86%) and mean PI (87%). The repeatability in evaluation of vascular pattern (85%), degree of vascularity (95%) and displacement of vessels (88%) are also high. Results suggest that power Doppler sonography is a reliable method in assessment of the vasculature of cervical lymph nodes. ; School of Optometry