The UN court for Rwanda handed a 30-year prison sentence on Tuesday to former army chief Augustin Bizimungu for his role in the 1994 genocide in which around 800,000 people were killed.
The court also convicted Augustin Ndindiliyimana, the former head of the paramilitary police, of genocide crimes, but ordered his release as he had already spent 11 years behind bars since his arrest.
The court ruled that while Bizimungu had complete control over the men he commanded, Ndindiliyimana had only "limited control" over his men after the start of the massacres on 6 April, 1994 and was opposed to the killing.
Two senior officers tried alongside the generals were also sentenced Tuesday.
Major Francois-Xavier Nzuwonemeye, the former commander of the reconnaissance battalion, was handed 20 years in jail for killing as a crime against humanity and murder as a war crime.
His subordinate, captain Innocent Sagahutu, was also sentenced to 20 years.
Bizimungu and Ndindiliyimana are two of the most senior figures to be tried by the Tanzania-based International Criminal Tribunal for Rwanda (ICTR) in connection with the genocide.
Ndindiliyimana was arrested in January 2000 in Belgium and Nzuwonemeye the following month in France. Sagahutu was detained in Denmark and Bizimungu in 2002 in Angola.
The case had been effectively adjourned since June 2009 when prosecutors requested life sentences for all four defendants while their defence lawyers asked for their acquittal.
The long-running case is known as the Military II trial.
In the Military I trial, Colonel Theoneste Bagosora, presented by the prosecutor as the brains behind the genocide, was sentenced to life in prison in December 2008, along with two other senior military figures.
Bagosora appealed and the hearing ran from 30 March to 1 April, but the appeal verdict has yet to be handed down.