There has been continued controversy as to the safety of egg-based MMR vaccine in egg-allergic children. Many studies haute dealt with MMR administrations to egg-allergic patients focusing on the systemic side reactions. It has been found that most egg-allergic patients do not react to MMR vaccine but to other vaccine components. Therefore, most authors conclude that if an individual can eat eggs without ill effects, he or she can take the MMR vaccine without skin testing. In this regard, this study describes two cases of systemic side reactions after injection of MMR vaccine to egg-allergic patients. In a case with a history of systemic reaction from egg ingestion, it is still recommended that skin testing with the vaccine be carried out. If the skin test result shows positive, incremental doses of the vaccine in every 15-20 minutes are suggested.