He held a press conference to announce his decision to resign a day after the Election Commission announced its decision to seek a ruling by the Constitution Court to disqualify him and 12 other Democrat MPs for having allegedly violated the charter by having stakes in media firm or companies which have received concessions from the government.
Suthep's resignation as an MP did not affect his Cabinet status as a Cabinet member is not required to be an MP.
He said he resigned so that he could go on working as the deputy prime minisetr instead of having to be suspended from duty had he case been submitted to the Constitution Court.
He insisted that his resignation was not a proof that he had done something wrong but he worried about his works as a deputy prime minister.
Suthep also insisted that he will not resign from the Cabinet.
He said the EC should resign if the Constitution Court later rules that the Democrat MPs did not violate the charter with their share holding.