A United Nations tribunal convicted Ratko Mladic, the Bosnian Serb former general, on Wednesday of war crimes, genocide and crimes against humanity in the slaughter of Bosnian Muslims during the breakup of Yugoslavia. He was sentenced to life in prison.

From 1992 to 1995, the tribunal found, Mr. Mladic, 75, was the chief military organizer of the campaign to drive Muslims, Croats and other non-Serbs off their lands to cleave a new homogeneous statelet for Bosnian Serbs.

Along with Radovan Karadzic, the Bosnian Serb leader, who was convicted on similar charges last year, Mr. Mladic was found to have orchestrated a campaign of so-called ethnic cleansing that made Bosnia and Herzegovina, a nation of 4.5 million at the time, the site of some of the worst atrocities of Europe’s bloody 20th century.