In egg-sensitive children, measles-mumps-rubella (MMR) vaccination may cause acute allergic reactions; therefore, current recommendations are to perform skin testing with the commercial vaccine before administration to egg-allergic children. In children with positive skin tests, desensitization with the measles-mumps-rubella vaccine should be done in order to administer a full dose of the vaccine. Twelve egg-allergic children, aged 12 months to 5 years of age, were referred to our pediatric allergy clinic for MMR administration over a 20-month period. Three children had positive skin prick or intradermal tests to the MMR vaccine. Two of these three patients experienced systemic hypersensitivity reactions while undergoing desensitization to the MMR. All reactions occurred with injections of the undiluted vaccine. Based upon this experience, we recommend that egg-allergic children should continue to have cutaneous tests done to the MMR vaccine and careful observation during desensitization in those children with positive skin tests.