"Mohan Bhagwatji talked about important national issues in his speech. The issues of social reform he raised are very relevant today," Modi said in a tweet.
The prime minister added: "On the Sthapana Divas (founding day) of RSS, I extend my good wishes to all Swayamsevaks."
In his address in Nagpur, where the Rashtriya Swayamsewak Sangh is headquartered, Bhagwat called for self-reliance in economy and denounced caste discrimination.
In Vijayadashami speech, RSS chief pats Modi govt; live broadcast on DD creates controversy