Rajasthan BJP president Madan Lal Saini died on Monday while undergoing treatment at AIIMS in Delhi, a party spokesperson said.
Mr Saini, also a Rajya Sabha lawmaker, was 75.
He was shifted to Delhi two days back owing to his deteriorating health conditions. Earlier, he was admitted at a private hospital in Jaipur due to infection in lungs.
He was appointed BJP state president last year. He was a former assembly lawmaker and RSS volunteer who held various posts in the Bhartiya Kisan Morcha as well.
Chief Minister Ashok Gehlot has expressed grief over his demise.
"Shocked and saddened to hear about the passing away of Madan Lal Saini ji, President of BJP, Rajasthan. My thoughts and prayers are with his family members. May God give them strength to bear this loss. May his soul rest in peace," Mr Gehlot tweeted.