Supporters of Siddaramaiah staged protests across Karnataka and gathered outside his Bengaluru residence urging him not to resign.
Protesters burnt tyres and raised slogans in Shivamogga and Yadgir, with many from the Kuruba community expressing anger over the leadership change.
Karnataka Law Minister H K Patil said Siddaramaiah informed ministers that D. K. Shivakumar would succeed him as chief minister following directions from the Congress leadership.