This study evaluates single operator test-retest reliability of spectral Doppler ultrasound measurement of median nerve excursion during wrist extension. Longitudinal motion of the median nerve was measured at the elbow on three occasions in both upper limbs of 16 healthy subjects using a standard colour Doppler ultrasound system. The mean of the three maximum velocity time integrals was calculated from the spectral Doppler sonogram of each test. Analysis of data with intraclass correlation coefficient indicated a high degree of repeatability (0.92). Spectral Doppler ultrasound may provide a valuable method for measurement of peripheral nerve motion and may have a role in the clinical assessment of entrapment syndromes.