Deekshabhoomi commemorates the place where Dr Ambedkar and thousands of his followers embraced Buddhism on October 14, 1956.
Sonia, Rahul and former Home Minister Sushil Kumar Shinde paid floral tributes to Ambedkar. Then they sat down near the urn containing his ashes with closed eyes.
"This is a matter of great happiness to have the opportunity to pay my respect and homage to Deekshabhoomi," Sonia Gandhi wrote in the visitors' book.
Chairman of Dr Ambedkar Smarak Samiti Bhante Sarai Sasai and close associate of Dr Ambedkar Sadanand Fulzele presented them mementos on the occasion.