This report provides medical validations for two conditions of concern regarding the health of Vietnam veterans - multiple sclerosis and motor neurone disease.It is the third supplementary report to Morbidity of Vietnam Veterans: Volume 3 Validation Study and fulfils the recommendation in Volume 1 of the study, the survey of male veterans, that the reported rates of multipe sclerosis and motor neurone disease be validated. This report further extends the knowledge about the health of Vietnam veterans and their families.