This study examines the effectiveness of two virtual reality simulators when compared with traditional methods of teaching intravenous (IV) cannulation to third year medical students. Thirty-four third year medical students were divided into four groups and then trained to perform an IV cannulation using either CathSim, Virtual I.V., a plastic simulated arm or by practicing IV placement on each other. All subjects watched a five minute training video and completed a cannulation pretest and posttest on the simulated arm. The results showed significant improvement from pretest to posttest in each of the four groups. Students trained on the Virtual I.V. showed significantly greater improvement over baseline when compared with the simulated arm group (p<.026). Both simulators provided at least equal training to traditional methods of teaching, a finding with implications for future training of this procedure to novices.