Mr Cridland has spent his entire career at the CBI, joining straight from university as a policy adviser in 1982.
He was deputy director-general from 2000 to 2010 and then director-general for five years - the first ever internal candidate to be given the role.
Headhunters Odgers have been appointed to look for a successor.
A CBI spokesman said: "This year marks the CBI's 50th anniversary and, with the election looming, John remains focused on ensuring the new government delivers pro-enterprise policies and championing British business at home and abroad."
John Cridland is to step down as director-general of the CBI, the lobby group for British business.