"Today, when we are celebrating the birth anniversary of Dr B R Ambedkar, I am pained to learn that the Prime Minister Manmohan Singh did not vote in the Assembly elections in Assam," Modi said, speaking to reporters at a seminar at the Pandit Deen Dayal Petroleum University here.
"Ambedkarji gave us the Constitution, and the Constitution gave us the right to vote. To know that the Prime Minister did not vote in the Assembly polls is a very saddening act, for the people of the country," he said.
"It is even more saddening, on the birth anniversary of Dr Babasaheb Ambedkar," Modi said.
The Prime Minister Manmohan Singh and his wife Gursharan Kaur are registered voters from Assam's Dispur Assembly constituency, where polling took place on April 11.
The Prime Minister has been a Rajya Sabha member from Assam for the last two decades.