Mukherjee, Ansari and former Prime Minister Manmohan Singh paid floral tributes at Vir Bhumi, the samadhi of Rajiv Gandhi.
Rajiv's wife and Congress president Sonia Gandhi, son and Congress vice president Rahul Gandhi, daughter Priyanka Vadra and her husband Robert Vadra, also laid flowers at the samadhi.
Senior Congress leaders Sushil Kumar Shinde, Motilal Vora, Mukul Wasnik, Mohsina Kidwai, Delhi Pradesh Congress Committee president Arvinder Singh and CLP leader Harron Yusuf were among the other leaders who paid tributes to the departed soul.
Devotional music was played throughout the programme.
Scores of members of the National Students Union of India (NSUI), the student wing of Congress, were also present on the occasion.
Rajiv Gandhi, who heralded the information and communication technology revolution in the country, was born on August 20, 1944 and served as the sixth Prime Minister of India from 1984-1989.He was assassinated by the LTTE on May 21, 1991 at Sriperumbudur in Tamil Nadu while addressing an election campaign.
In Uttarakhand, Chief Minister Harish Rawat paid tribute to Rajiv Gandhi and said his contribution to the development of the nation can never be forgotten.