"Wishing the Kerala Chief Minister Shri Oommen Chandy a happy birthdy. I pray for his long life and good health," Modi tweeted.
Keeping away from any special birthday functions, Chandy, fondly called 'OC' by his followers, attended various civic poll campaign meetings at his home town Kottayam today, Chief Minister's office sources said.
Before leaving for Kottayam, he offered prayers at a church here.
This is Chandy's second stint as Chief Minister.
He had assumed charge for the first time after senior leader A K Antony resigned from the post in 2004, following Congress' defeat in the Lok Sabha polls that year.