Hitting out at Prime Minister Narendra Modi, Siddaramaiah said his "speeches are completely hollow and have made no impact on the voters of Karnataka".
The Congress leader claimed Modi's "image has drastically declined" when he campaigned for the elections in the state.
Mocking at Amit Shah, the incumbent chief minister said the BJP President is like a "comedy show".
Siddarmaiah also dubbed his political rival and BJP's chief ministerial candidate B S Yeddyurappa as "mentally disturbed" on his claim that he would form the next government in the state.
"Congress will get the clear majority. There is no confusion about this. We are very confident that Congress will come back to power with clear majority. He (Yeddyurappa) is mentally disturbed. BJP can't get more than 60-65 seats," Siddaramaiah said.
The results of the Karnataka elections will be declared on May 15.