The investigation is a continued examination of the dental and skeletal changes accompanying rapid maxillary expansion on 23 patient. It also examines the stability of these changes 5 years post retention The results show that the final increase in width between the upper first molars recorded 5 years post retention Was 45 percent of that initially achieved by rapid maxillary expansion. The mean final increase in the inter canine width was only 23 percent of the expansion achieved initially. The results do not support the common belief that rapid maxillary expansion increases the overjet and reduces the overbite. No unfavourable skeletal and dental side effects of rapid maxillary expansion could be found.