Congress MLA and former Karnataka Minister Tanveer Sait was attacked by a man, with a knife, at a wedding ceremony in Mysuru late on Sunday night, police said.
Sait, the Narasimharaja constituency MLA, was immediately rushed to a hospital in Mysuru, where he underwent a surgery, they said.
The attacker has been identified as Farhaan Pasha, aged about 25 years.
As Sait was seated at the function, Pasha attacked him with a knife and tried to escape, when he was caught by the people at the venue and later handed over to the police.
The incident has been caught on video at the event.
Pasha is being interrogated, police officials said.