"I convey my heartfelt wishes to our beloved President, Shri Pranab Mukherjee on his birthday. I pray for his long and healthy life," Modi tweeted.
"President Mukherjee's long years in public life make him an invaluable asset to our nation. His wisdom and intelligence have few parallels," Modi wrote.
In another tweet Modi said Mukherjee had always been a respected leader with friends and well-wishers across the political spectrum.
Born on December 11, 1935 in Mirati (West Bengal), Mukherjee has a political career spanning six decades.