The ministers from the ruling right-wing Bharatiya Janata Party (BJP) were filmed by local television watching graphic footage on their mobile phones on Tuesday while other lawmakers in the house were debating legislation.
"We have resigned to avoid embarrassment to our party and not give the opposition an opportunity to disrupt the assembly proceedings today," state minister for cooperation Laxman Savadi told reporters.
"We were watching a clipping of an incident for a discussion on the rave parties held at St. Mary's Island (on the western coast of Karnataka). It was not a porn clip," he explained.
Karnataka's minister for women and child development, C.C. Patil, and minister for ports and fishery Krishna Palemar also stepped down.
In the television footage, the ministers can be seen watching the indecent video. They passed their mobile phones amongst themselves.