Emmanuel Nteziryayo, Charles Munyaneza, Celestin Ugirashebuja, Vincent Bajinya and Celestin Mutabaruka were held by a police extradition unit and appeared today in a London court.
Police say the five men, who were living in various parts of England, are accused by Rwandan prosecutors of involvement in the 1994 ethnic genocide, in which an estimated 800,000 people died.
A previous attempt to extradite all of the suspects except Mutabaruka was halted in 2009 by Britain's High Court, which said they might not receive a fair trial.