Republic Day marks the adoption of India's republican constitution in 1950 - three years after independence from Britain.
French President Nicholas Sarkozy was the guest of honour at the parade during which India's latest military hardware was displayed.
Tens of thousands of people gathered in the centre of Delhi, once the heart of India's colonial past.
In Bangalore, Indian school children performed a drama based on the Indian struggle for independence.
Indian soldiers from the Light Maratha Infantry performed a traditional sport called Malkhumb.
Tight security was in place, especially after calls to boycott the day by separatists fighting Indian forces in Kashmir.
The parades were also a chance for India to display its military might.
Soldiers in colourful headgear marched smartly, while India's latest weapons - including nuclear missiles - were also on display.