Ringleader Batiste faces 70 years and Stanley Phanor 30 years
Five men have been convicted in Miami of plotting to blow up the Sears tower in Chicago and carry out attacks on FBI offices across the United States.
Prosecutors say the men conspired to provide material support to al-Qaeda, but defence lawyers argued the whole thing was an FBI set up.
A sixth man was acquitted of all charges. It was the third trial for the men, who were arrested in 2006.
Previous juries were unable to agree on whether their plot was genuine.
In the earlier trials, a seventh man was also acquitted of all of the charges he faced.
The latest verdicts were handed down after six days of deliberations.
The men - who were known as the Liberty City 7 after the poor area of Miami they operated in - now face 30 to 70 years in prison.
Sentencing has been set for 27 July.
'Kill the devils'
The men, most of whom have Haitian backgrounds, were caught on tape by an FBI informant discussing plans to cause an anti-government insurrection.
Two previous trials ended with hung juries unable to reach a verdict
The ringleader, Narseal Batiste, 35, is caught on audio and video tape saying that they should start a "full ground war" that would "kill all the devils".
Defence lawyers argued that the group had not been serious about the attacks, and that they went along with the plot in order to con the FBI agent out of $50,000 (£32,700).
Batiste, convicted on four terrorism-related conspiracy counts, faces up to 70 years in prison.
His right-hand man, 29-year-old Patrick Abraham, was convicted on three counts and faces 50 years behind bars.
Three others, Burson Augustin, Rotschild Augustine and Stanley Grant Phanor - aged 24, 25 and 33 respectively - face 30 years on two counts.
Naudimar Herrera, 25, was cleared of all four charges.