International Buddhist Conference which began on Saturday at Mumbai.
The meet is to mark the 50th anniversary of Ambedkar's conversion to Buddhism. Rajapaksa said that it was a "joyous" occasion.
According to media reports about 100,000 Dalits are expected to convert to Buddhism during the conference.
"I call upon Buddhists in India, Sri Lanka and worldwide, to promote the teachings of the Buddha, especially metta (loving kindness),karuna (compassion), mudita (rejoicing in other's good fortune) and upeka (equanimity)," Rajapaksa said.
"The Buddha's teachings could contribute to the evolution of a world in which peace and harmony reign."
"Dr. Ambedkar's mission should live long, guiding humanity on the correct path, " Rajapaksa said.
Ambedkar observed Buddhism in Lanka
The Sri Lankan President recalled that Dr.Ambedkar had visited Sri Lanka in 1950 as Indian Law Minister and had participated in the International Buddhist Conference held in Kandy.
"His lectures delivered here then were very popular," Rajapaksa recalled.
Ambedkar actually converted to Buddhism only on October 14, 1956, six years after he came to Sri Lanka to study the practice of Buddhism in the island, the only country in the South Asian region where Buddhism had survived.
His conversion became a reality a good 22 years after he organised a conference of Mahars (Dalits of Maharshtra) to get a stamp of approval
on conversion from Hinduism to other faiths.
During the Kandy conference on May 25, 1950, Ambedkar had said that he wanted to find out to what extent Buddhism was a "living thing" among the people of the island country.
"I am here to find out to what extent there is dynamics in the Buddhist religion as far as the people of this country are concerned," he said.
According to sources, initially, the Sri Lankan government wanted to send a delegation for the Mumbai meet, but they gave it up because such a gesture might become controversial. They were not sure if the Hindutva forces would take the mass conversion from Hinduism with equanimity.
Mayawati's victory welcomed
The astounding and unexpected victory of Mayawati in the recent Uttar Pradesh assembly elections has been welcomed in Sri Lanka.
The Dalit leader had become the favourite subject among the intelligentsia and the middle class.
Mayawati's frontal assault on India's "arrogant and hegemonic ruling class" is hailed here as a healthy development.