Less than 48 hours before the Eagles were due to begin their Barclays Premier League campaign at Arsenal, Pulis, whose appointment last November triggered a remarkable run from likely relegation to comfortable survival, departed the Selhurst Park club.
Press Association Sport understands Palace will issue a statement later today to address the resignation before holding an afternoon press conference.
Palace staff were surprised with the speed at which Pulis went from preparing his team for the trip to the Emirates Stadium to cutting ties with the club.
He and co-chairman Steve Parish held talks to discuss transfer issues on Thursday afternoon.
Pulis had reportedly been left frustrated by the club failing to push through deals for various players he targeted to strengthen the Palace squad.
It was not immediately known whether Pulis had resigned, been sacked, or left by mutual consent.
Bookmakers had earlier drastically cut the odds on Pulis being the next Premier League manager to leave his post, with some closing the market due to heavy betting on the Welshman, who had gone from being a 40/1 shot on Wednesday to an odds-on favourite.
Pulis inherited a team in turmoil last autumn, but such was the job he did, guiding the team to an 11th-placed finish, that he was named the League Managers Association's Premier League manager of the year in May.
The exit of Pulis came on the day Palace clinched the signing of Liverpool defender Martin Kelly on a three-year contract.
The 24-year-old made his Reds debut back in 2009 but found first-team opportunities limited, with a serious knee injury also ruling him out for a year.
Kelly, capped once by England in a 2012 friendly against Norway, became Pulis' fourth signing of the summer following the acquisitions of Chris Kettings, Fraizer Campbell and Brede Hangeland.
Source : PA
Source: PA