Public Printer Davita Vance-Cooks said the GPO first printed the report in 1964, Roll Call reported.
By downloading a PDF copy of the document, readers can view Lee Harvey Oswald's visa application and reports from doctors at Parkland Hospital in Dallas who treated the president.
Another 26 volumes of hearings conducted under the chairmanship of Chief Justice Earl Warren also are available. Some of them were unclassified in the mid-1990s; others are still unavailable to the public.
Recordings of conversations made the day of the assassination between Washington officials, Air Force One pilots and people on board the flight from Dallas to Andrews Air Force Base also are posted online.