The decision had been taken in the wake of telecom tariff order issued by Trai, the company said in a statement.
Roaming tariff for incoming calls has been cut by 40%, STD by 23% and 20% for local calls.
Local and national SMS tariff has been reduced by 75%, the statement said.
Earlier, BSNL had announced free unlimited calls from landline to any landline from nine in the night to seven in the morning which is also with effect from May 1.
This announcement comes just two days after Airtel, Vodafone and Idea Cellular also cut their respective roaming charges.