By-elections to fifteen state assembly constituencies were held in Karnataka on 5 December 2019, and results were announced on 9 December. As the ruling party, BJP needed to win 6 out of the 15 seats to maintain its majority. BJP won 12 seats, Congress won two, JD(S) failed to open its account, and one seat was won by a rebel BJP leader who contested as an independent.
By-elections to fifteen state assembly constituencies were originally to be held on 21 October 2019 together with Haryana and Maharashtra Assembly elections. The counting of votes was to be on 24 October 2019.
The Election Commission on 27 September rescheduled the by-elections to 15 Karnataka assembly constituencies to 5 December and will declare the results no later than 11 December.
The bypolls were required after 15 MLAs, from Congress and Janata Dal (S), resigned to bring down Kumaraswamy's coalition government.
BJP won 12 of the available 15 seats. After Roshan Beg from Shivajinagar had resigned, BJP did not allow him to join them; Beg was unable to contest the bypoll and Congress retained the seat.
From Hoskote, MTB Nagaraj resigned his seat and joined BJP, who had nominated him from his former seat. Nagaraj was challenged by a BJP rebel, who won the seat.
From Hunsur (Hunasuru), Adagur Vishwanath had previously won on JD(S) ticket, defeating Manjunath of Congress. Vishwanath resigned and contested as a BJP candidate, however Manjunath managed to win the seat for Congress.