Police found explosives, grenades and an assault rifle during the raids that took place in Lucknow, said S K Agarwal, an Uttar Pradesh state official.
The authorities believe the suspects may have been planning an attack in Lucknow, the state capital.
The March 7 bombings took place almost simultaneously at an ancient temple packed with devotees and a crowded railway station, killing over 20 people and injuring 68 in India's most important city for Hindu pilgrims.
The suspects were thought to be members of Harkat-ul Jehadi Islam, a Bangladesh-based offshoot of Jaish-e-Mohammed, which is fighting Indian rule in Kashmir, Agarwal said.
The authorities were trying to find out the nationalities of the arrested men but they were believed to have trained in Pakistan, said Bua Singh, the top police official in Uttar Pradesh.
Lashkar-e-Kahar, a Kashmiri group, claimed responsibility for the bombings soon after the attacks in a phone call to a local newspaper.