"On the special occasion of Magh Bihu, my greetings to the people of Assam," he said.
"Uttarayan greetings to the people of Gujarat," Modi said in another tweet.
He tweeted the messages in local languages also.
"May these festivals bring abundance of happiness and prosperity in the lives of our hardworking farmers, he said.
"These & many other festivals celebrated across India add great colour & happiness in our lives. This diversity is India's greatest strength," the Prime Minister said.