Transrectal three-dimensional (3-D) contrast-enhanced power Doppler ultrasound (US) is a novel technique for studying possible prostate malignancy. Before studies can be performed to investigate the clinical validity of the technique, reproducibility of the contrast US studies must be proven. Reproducibility of contrast US was studied in 10 patients with biopsy-proven prostate cancer. The studies performed included static investigations and dynamic investigations of the prostate vasculature. All studies were double performed. The assessment of reproducibility was done objectively using a computer program and, subjectively, by visual assessment. The results indicate high reproducibility of static contrast investigations, for both the objective and subjective assessment. The subjective assessment of the dynamic studies was also highly reproducible. The objective assessment of the dynamic contrast studies, however, was less reproducible, mainly due to motion artefact. We concluded that, especially static 3-D contrast-enhanced, power Doppler investigations of the prostate are highly reproducible.