During the visit, Manmohan Singh was expected to announce a relief package of 40 billion rupees ($865 million) directed at waiving off loans, improving irrigation and encouraging diversified farming, newspaper reports said.
The tour will take him to the Vidarbha region of western Maharashtra state, where he will meet families of farmers who have ended their lives.
Federal government officials say more than 8,900 farmers have committed suicide since 2001 in four states hardest hit by an ongoing agricultural crisis, including 980 in Maharashtra alone.
The number has been dismissed as far too low by activists and, according to a state government-backed report, more than 4,100 farmers ended their lives in Maharashtra in 2004 alone.
Rights activists say farmers are being driven to commit suicide by mounting debts - loan sharks demand up to 120% annual interest - failed harvests and the tumbling price of cotton, the region's main crop.
The prime minister's visit is being seen as a sign that the government is taking the situation seriously.
Agriculture is essential to the well-being of the Indian society as it employs about 60% of the country's workforce and accounts for a quarter of India's GDP.
Federal government figures say that close to one million farmers committed suicide between 1995 and 2003 nationwide.