Martin McGuinness has resigned as Mid-Ulster MP.
He said the decision was in line with Sinn Fein's commitment to end double jobbing and planned to concentrate on his job as Stormont MLA and Deputy First Minister.
Francie Molloy will run for the seat in his place.
Mr McGuinness said: "I am resigning as MP but I have no intention of leaving Mid-Ulster. South Derry and East Tyrone have suffered immensely as a result of the conflict.
"I will always be grateful to the people of this area for trusting me to represent them and their interests.
"I will of course continue to represent the Mid-Ulster constituency in the Assembly. I am honoured to do so both as an MLA and as Deputy First Minister in equal partnership with Peter Robinson."
He was elected MP for Mid-Ulster in 1997.