The names of Zubeidat and Tamerlan Tsarnaev were put on the watch list in 2011 at the request of the CIA, ABC News reported Friday.
Tamerlan Tsarnaev was killed in a shootout with authorities after the bombings killed three people and injured more than 260. His brother, Dzhokhar, was wounded in the police encounter and is hospitalized.
Tamerlan and his mother were placed in the Terror Identities Datamart Environment after the Russian government advised the CIA it considered them to be potential Islamic militants.
An earlier investigation by the FBI, also at the request of the Russian government, found Tamerlan Tsarnaev did not have ties to terrorism.
Some 700,000 names are on the low-level TIDE list, which serves as a source for other federal agencies to compile their own watch lists.
Inclusion on TIDE does not mean the individuals are suspected of conducting terrorist activities, are under surveillance or face travel restrictions.
Zubeidat Tsarnaev could be arrested should she return to the United States, The Wall Street Journal reported. She faces felony charges that she shoplifted dresses valued at $1,624 from a Lord & Taylor store in 2012. She left the country before going to trial.