"I called up Shri Rajnath Singh ji and congratulated him. He brings with him vast experience of both organisation and administration," Modi said on micro-blogging site twitter.
"Rajnath Singh ji served as agriculture minister in Atal ji's government (A.B. Vajpayee). He has always been associated with the farmers. BJP will gain from this," he said.
In dramatic developments Tuesday, incumbent BJP president Nitin Gadkari announced that he would not seek a second term. Former Uttar Pradesh chief minister Rajnath Singh emerged as Gadkari's likely successor.
Rajnath Singh's name emerged after a series of meetings involving party leaders Arun Jaitley, Venkaiah Naidu, Ram Lal and Ananth Kumar.
BJP leaders are meeting in Delhi and name of the new president is likely to be announced later during the day.