Pranab Mukherjee unfurled the national flag at his residence in central Delhi.
A day after his name was announced for the Bharat Ratna award, former President Pranab Mukherjee called upon Indians to strive to protect and preserve the foundational ethics of justice, liberty, equality and fraternity as enshrined in the Constitution.
Wishing fellow citizens on the 70th Republic Day, he urged them to strengthen their resolve to live up to the ideals of the Constitution.
"As the Indian republic turns 70 years old, I wish each & every citizen in India and abroad a very Happy Republic Day. The foundation of this Great Democratic Republic was laid down by our Founding Fathers in our Indian Constitution," he said on Twitter.
Mr Mukherjee also unfurled the national flag at his residence in central Delhi and took the salute from a contingent of CRPF personnel deployed there.
"Our Founding Fathers have guided us this far, let us go farther with greater vigour and spirit to create an India of our dreams. On this Republic Day, let us strengthen our resolve to live up to the ideals of our Constitution.
"The dynamism of our Constitution exemplified in the ideals of Justice, Liberty, Equality and Fraternity sets the tone of our development. We must strive to protect and preserve these foundational ethics," he also said.
The government Friday announced conferring on Mr Mukherjee the country's highest civilian award - the Bharat Ratna -- for his contribution to public life. The late singer Bhupen Hazarika and the later Jana Sangh leader Nanaji Deshmukh were also conferred the Bharat Ratna.