Access to Congressionally Mandated Reports Act This bill requires the Government Publishing Office (GPO) to establish and maintain a publicly available website containing copies of all congressionally mandated reports. A federal agency must submit a congressionally mandated report and specified information about the report to the GPO concurrently with submission of the report to Congress. Federally chartered organizations and the Government Accountability Office are excluded from the requirements of this bill. The Office of Management and Budget must issue guidance to federal agencies on the bill's requirement for agencies to submit copies of congressionally mandated reports and related information to the GPO. At least annually by April 1, the Library of Congress must submit to the GPO a list of all congressionally mandated reports from the previous year.