Murison joined NME in 2003 as a staff writer, but became the first female editor of the magazine in July 2009 after Conor McNicholas left to join Top Gear magazine.
She left NME in 2008 to spend almost a year in New York working at Nylon magazine, but her return was widely acknowledged within the music industry as a successful move that revitalised the weekly title.
During her time as editor, she presided over a major redesign of the magazine, "survived" an interview with The X Factor supremo Simon Cowell in 2010 and was awarded BSME's 'New Editor of The Year'.
"My last three years at NME have been exhilarating, inspiring and completely unforgettable," she said.
"I am incredibly proud to have played a small part in the story of the world's greatest music magazine and leave happy in the knowledge that the current NME team is amongst the most talented and passionate in its 60-year history."
NME publishing director Emily Hutchings added: "Everyone at NME is obviously sad to see a talent like Krissi go, but due to her great achievements while working as editor she leaves NME in great health and the brand is stronger than ever.
"We have an immensely talented editorial team who will continue to push the brand forward and will carry on their success of creating first-class content. We wish Krissi all the best in the future."
Murison, the eleventh editor of NME, will step down later in the year and an announcement on her successor will be made "in due course".
Meanwhile, IPC Media announced today that NME - celebrating its 60th year in publishing in 2012 - will be among the first UK brands to feature editions on Google Currents, a new magazine-style news reader app for Android and iOS.
"On NME, we're constantly striving to make our services more innovative, more powerful and more usable," said Hutchings.
"Google Currents is yet another way in which our audience of avid music fans can connect with their favourite music brand, keeping them up to date with everything that's happening in live music on a daily basis.
"We want to be everywhere our users want us to be and our new Live edition on Google Currents allows us to do just this."