- Postal Rates Special Joint Subcommittee9
- Postal Salaries Joint Commission6
- Postal Savings System8
- Postal Service Joint Commission20
- Postwar Immigration and Naturalization, Select Committee to Investigate and Study Laws and Problems Relating to, House1
- Presidential Campaign Activities, Select Committee on, Senate1
- Presidential Campaign Expenditures, Special Committee Investigating, Senate5
- Presidential and Senatorial Campaign Expenditures, Special Committee on Investigation of, Senate3
- Presidential, Vice Presidential, and Senatorial Campaign Expenditures, 1940, Special Committee to Investigate, Senate1
- Presidential, Vice Presidential, and Senatorial Campaign Expenditures, 1944, Special Committee to Investigate, Senate4
- Presidential, Vice Presidential, and Senatorial Candidates in 1936, Special Committee to Investigate Campaign Expenditures of, Senate1
- Printing Committee299
- Printing Committee, House251
- Printing Committee, Senate45
- Printing Investigation Commission5
- Printing Joint Committee83
- Private Land Claims Committee29
- Privileges and Elections Committee95
- Privileges and Elections Committee, Senate47
- Propaganda or Money Alleged to have been used by Foreign Governments to Influence United States Senators, Special Committee to Investigate, Senate5