President Pratibha Patil, Prime Minister Manmohan Singh and the departed leader's wife and Congress chief Sonia Gandhi went to the late leader's memorial 'Vir Bhumi' here and paid their respects.
Rahul and Priyanka also paid floral tributes at the memorial of their father, who was assassinated on May 21, 1991 at Sriperumbudur in Tamil Nadu during a poll campaign.
Vice President Hamid Ansari, Delhi Lt Governor Tejinder Khanna, Delhi Chief Minister Sheila Dikshit, Parliamentary Affairs Minister P K Bansal and Urban Development also paid homage to Gandhi. Priyanka's husband Robert Vadra was present on the occasion.
School children waving national flags were also present at the memorial.
A speech by the late prime minister, during which he talked about preserving the dignity of institutions, was played at the programme.