The date for the start of his trial has not yet been fixed.
Medunjanin, who is charged with being involved in a case that includes one of al-Qaeda"s top operatives, Adnan Shukrijumah. pleaded not guilty in federal court in New York on Friday.
The 25-year-old Medunjanin, who arrived in the USA with his family in 1994 and who holds U.S. citizenship, insists on his innocence in relation with charges that he and his two schoolmates of Afghan origin had planned to carry out three co-ordinated suicide attacks on Manhattan subway lines.
Medunjanin has been in custody since his apprehension at the start of this year. He was then arrested together with another suspect -- Zarein Ahmedzay -- of Afghan origin in the Flushing area of Queens, New York.
According to an indictment unsealed by the Brooklyn court, three al-Qaeda operatives in Pakistan, including Adnan Shukrijumah, plotted attacks to be carried out by home-made explosives in subway lines in New York in September 2009.
The 34-year-old Shukrijumah reportedly recruited Medunjanin and another two men -- Najibullah Zazi and Zarein Ahmedzay -- while they were staying in Pakistan for this task.
The guilty verdict carries a sentence of life in prison.