Atal Behari Vajpayee said he was contesting elections so that he can continue maintaining peace in Kashmir and northeastern states.
"I have contested elections for 40 years," Vajpayee said. "This time I was not keen. But then I thought I must shoulder the responsibility, otherwise our country will fall apart.
"There is peace in Kashmir, peace in the northeast," NDTV quoted Vajpayee as saying.
Opinion polls have indicated the Vajpayee-led multi-party coalition will retain power in the upcoming elections. The five-phase polling will begin April 20 and end May 10 in what is described as the biggest vote in the world.