The Massachusetts Military Affidavit is a legal document used to document the service of a person in the military. It is used to prove the identity, service history, or other information about a person who has served in the Massachusetts military. There are two types of Massachusetts Military Affidavit: the Massachusetts National Guard Affidavit and the Massachusetts Active Duty Affidavit. The Massachusetts National Guard Affidavit is used to document a person's service in the Massachusetts National Guard and is usually used for purposes such as obtaining a veteran's benefit or proving eligibility for a veteran's discount. The Massachusetts Active Duty Affidavit is used to document a person's service in the active duty armed forces of the United States and is usually used for purposes such as obtaining a veteran's benefit or proving eligibility for a veteran's discount.