President Pratibha Patil, Vice President Hamid Ansari and Congress president Sonia Gandhi were present at a function held in Delhi.
Several functions are being organised in different parts of the country to mark the occasion.
Dr Ambedkar spent his life fighting untouchability and the Indian caste system.
He is also credited for having sparked off the Dalit Buddhist movement and was honoured with the Bharat Ratna for his contribution to Indian society.
Overcoming numerous social and financial obstacles, Ambedkar became one of the first 'untouchables' to obtain a college education in India.
He went on to pursue higher studies in the United States and England, where he earned law degrees and multiple doctorates for his study and research in law, economics and political science.
Returning home as a famous scholar, Ambedkar practiced law for a few years before he began publishing journals that advocated political rights and social freedom for India's untouchables.
Image: Hundreds of of followers of Dr B R Ambedkar congregated at 'Chaityabhoomi' near Shivaji Park in Mumbai, where the Dalit icon was cremated | Photograph: Sahil Salvi
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