Mike Baird says the decision hasn't been easy but it's the right time for him to step down as the NSW premier. Watch the video below.
"It has taken a lot of deliberation - but I strongly believe it is the right decision. Really, there's a couple of reasons for that. In my maiden speech, I spoke about wanting to come into public life to make a difference. I was frustrated by what I saw - a lack of action - and I was determined to try and get things done," said a visibly emotional Mr Baird.
"After 10 years in public life, three years as Treasurer and three years as premier, I think now is the right time to do this," he told reporters in Sydney on Thursday.
"Secondly, there is a strong personal cost that comes in public life."
Mr Baird announced via Twitter just after 9am on Thursday that he was retiring from politics.
"It's been an honour to serve you, NSW," he tweeted.
"There is a strong personal cost that comes in public life. I've probably felt that more than any other time in the past few months.
"My father and my mother and my sister are going through a very serious health challenge and, to be honest, at times I have been in pain not being able to spend the time that I should."
Mr Baird said is leaving behind a great team which is going to do many more great things for the state.
Mr Baird touched on the economy, infrastructure, education and social welfare as his key legacies to the state.
"The economy - remember what New South Wales was like? It was a basket case. It now has the strongest economic growth, it has got the strongest jobs growth, it has got the strongest and highest housing approvals in the nation, and the lowest unemployment rate.
"Things that don't happen by chance, but with a lot of hard work, and we were proud to do that," he said.