Home Ministry sources said the decision was taken at a high-level meeting.
"The decision has been taken to ban CPI-Maoist under the Unlawful Activities (Prevention) Act as a terrorist organisation," they said.
CPI-Maoist, which is the main Naxal group in the country, has been bracketed with 34 other organisations including Lashkar-e-Tayiba [Images] and the Students' Islamic Movement of India, who are in the list of banned outfits.