We investigated the retention of knowledge and skills after repeated Virtual World MOS (VWMOS) team training of CPR in high school students. An experimental group of 9 students were compared to a control group of 7 students. Both groups initially received traditional CPR training and the experimental group also received 2 VWMOS sessions six months apart. Although we found no significant differences in general basic life support knowledge, the changes that occurred in the CPR guidelines were retained 18 months after the last Virtual World training session in the experimental group. Moreover fewer deviations from the CPR guidelines occurred.