"I have made mistakes. I am human. But the attacks on my integrity have started taking a toll on those around me and this is unfair on them."
Mr Gilmore said he'd advised the National Party's whips of his decision.
"I also want to make clear my support for the National Party and Prime Minister John Key remains unwavering."
National Party President Peter Goodfellow said "Aaron has had a tough decision to make. Today he has put his loyalty to the Party first in announcing his intention to resign his List seat."
"This has been an extremely difficult decision for him, and I want to acknowledge that."
Mr Gilmore said that he is extremely honoured to have been a member of the New Zealand Parliament and has always worked to make the lives of the people of Christchurch better.
Mr Gilmore wished to express gratitude to his family and friends who have shown support and understanding over the past two weeks.
"Finally, I want to apologise once again to all those people who I've let down with my behaviour. I'm determined to learn from those lessons as I continue my life with more grace and humility.
"I will seek to make a final statement in Parliament on Tuesday."
Pressure on Mr Gilmore to resign intensified on Friday after it was revealed he was warned about sending inappropriate emails while working at a government department - an allegation he denied a few days earlier.
That was just a few days after Mr Key made it clear he thought Mr Gilmore should resign after a text message exchange between Mr Gilmore and his dining companion at Hanmer Springs Andrew Riches emerged which undermined what he had told Mr Key's office about that evening.
Mr Gilmore's resignation comes after he returned to his Christchurch home while other party members attended a conference in Whanganui.
Speaking to reporters at the conference today, Mr Key said Mr Gilmore had returned home "to reflect on his next move with his family".
Mr Key's frustration with the allegations surrounding his bottom-ranked MP became increasingly evident in recent days with the Prime Minister late last week saying: "I don't really think New Zealanders give a toss about him".
Mr Key had indicated that Mr Gilmore's departure would not affect this week's Budget vote because National would have the numbers without him.
Mr Gilmore, 39, entered Parliament in 2008 on the list. In 2010, he was forced to correct his CV after the Herald revealed he had claimed a high-level finance industry qualification which he did not have.
The next person on National's list is Claudette Hauiti, a former Maori broadcaster.