A letter from the lawmakers asking the GOP governor to leave office was delivered to Sanford shortly after noon Wednesday.
The letter follows one sent a day earlier by House Speaker Bobby Harrell asking for Sanford's resignation.
The moves are significant in part because any move to impeach the governor would begin in the House, which has 73 Republicans and 51 Democrats.
Calls for Sanford to resign or be impeached have grown since his June revelation of a yearlong affair. The State Ethics Commission is investigating his travel.
Sanford has said he has no plans to quit. He has been seeking traction for his legislative agenda in his final 16 months in office.
READ THE LETTER:
Click here to read the letter from the South Carolina House republicans.