Governor Ram Naik hoisted the tri-colour at the Vidhan Sabha here and took the salute of impressive parades put up by the Army, central forces and school children.
Students of different schools also made colourful presentations during the celebration.
Chief Minister Akhilesh Yadav, cabinet ministers and state officials among other dignitaries were present at the function.
On the occasion, different state departments and schools brought out impressive tableaux.
The Governor asked people to re-dedicate themselves to the service of the nation and exhorted them to come out to vote in the UP Assembly elections beginning February 11.
Republic day functions were also held in all government and political party offices with unfurling of the national flag and singing of patriotic songs.
There was no report of any untoward incident anywhere in the state so far, police said.