Jugantar or Yugantar (Bengali: যুগান্তর Jugantor) (English meaning New Era or more literally Transition of an Epoch) was one of the two main secret revolutionary trends operating in Bengal for Indian independence. This association, like Anushilan Samiti started in the guise of suburban fitness club. Several Jugantar members were arrested, hanged, or deported for life to the Cellular Jail in Andaman. Thanks to the amnesty after World War I, most of them were released and could give a new turn to their political career, mainly: (a) by joining Deshbandhu's Swarajya or (b) the Communist Party of India; or (c) M. N. Roy's Radical Democratic Party; or (d) later Subhas Chandra Bose's Forward Bloc in the '30's.
This party was established by leaders like Aurobindo Ghosh, his brother Barin Ghosh, Bhupendranath Datta, Raja Subodh Mallik in April 1906. Barin Ghosh and Bagha Jatin were the main leaders. Along with 21 revolutionaries, they started to collect arms, explosives and manufactured bombs. The headquarters of Jugantar was located at 27 Kanai Dhar Lane, then 41 Champatola 1st Lane, Kolkata.