Graham Murray says he quit the struggling Cowboys to save the club from sliding further into the abyss.
Murray confirmed rugby league's worst kept secret on Monday afternoon when he announced he would be departing 10 rounds into the final year of his contract.
Assistant Ian Millward is expected to take the reins for the rest of 2008 before handing over to Neil Henry in 2009.
Murray was told before the start of the season that 2008 would be his final year, but the form of the 15th-placed Cowboys hastened his exit.
"It's been in my mind for a couple of weeks. It's certainly not an easy one and it's not the way I wanted to leave," he said.
"But I've tossed it around in my head and I think the best way forward is for me to step aside and give someone else a go and try and get us back up to where we were."
"I don't want to be someone who steps away from something but I just think it's in the best interests of the club."
"This is about trying to get the club back on track."
"It's best for me and the club for me to resign. If you're not at the top of the table something's got to give."
North Queensland has slid down the table in recent weeks, with last Saturday's 38-6 loss to Manly the fourth defeat in succession.
"The buck stops with me and unfortunately we're running 15th on the ladder and I don't think anyone wants to be there - me or the players," Murray said.
"I don't feel comfortable losing four in a row. I want them to be back at the top where they should be."
"I'd like them to climb the ladder."
Cowboys football manager Dean Lance confirmed Millward was likely to be appointed interim coach within the next 24-48 hours.
Lance said of Millward: "With his experience winning championships in England and being Graham's assistant, he's certainly be in the firing line to take over the position."