Nearly three years ago, he won a sweeping national election victory with promises to develop the economy and root out corruption.
Now India is just emerging from the fallout of a November decision that withdrew India’s two largest currency notes from circulation and caused weeks of chaos as people waited to get their money back in new bills.
Mr Modi and his Bharatiya Janata Party hailed the move as a way to curb tax fraud and corruption and push India towards more digital spending.
Opponents have said it was a self-inflicted blow on the world’s fastest-growing economy, causing enormous hardship for the vast majority of Indians, who often rely completely on cash.
While the five state elections will not decide whether Modi remains in office, a loss would be seen as a serious blow to his political image.
Most important is the northern state of Uttar Pradesh, whose immense population of 204 million means state elections often help shape the national political agenda.
“In these elections, Uttar Pradesh is the real biggie,” said Ajoy Bose, a political analyst in New Delhi.
“If the BJP were to lose in Uttar Pradesh, it would be a huge setback, both for the party and for Modi. It would destroy the myth of Modi, who has been projected as this political juggernaut of invincible proportions.”
Elections were held at the weekend in the northern state of Punjab and the beach resort state of Goa.
Hundreds of paramilitary troops and police were posted near voting stations across Punjab to ensure security as voters stood in long queues to cast their ballots.
When voting ended in Punjab, around 83 per cent of the state’s eligible voters had cast ballots, with an even higher turnout in Goa.
In the next phase of the election, the Himalayan state of Uttarakhand votes on 15 February, and remote north-eastern Manipur on 4 and 8 March. Elections in Uttar Pradesh begin on Saturday, but because of the state’s size, voting is divided into seven phases. Results will be declared on 11 March.
Mr Modi’s performance in the state-level polls is likely to determine his political strategy in the run-up to the next national elections due in 2019.