Cook, Vanarama National League South Manager of the Month for April, helped insure their survival.
Having gone 17 games without victory when he took over in January, the club were face a huge fight to stay up.
But he turned things around - and winning four of their last five games convinced the board he was the man to club needed in charge next season.
Clearance came through from the Professional Footballers’ Association on Monday and he has been given the green light to remain at the helm.
“We are pleased to announce that the PFA have given their approval for Mike Cook to remain as our First Team Manager for the 2019-20 season,” a club statement confirmed.
“Cook took charge of City in January and ensured our status at this level was retained following an impressive end to the season; with the club finishing 17th in the National League South with 47 points.
“Cook will be joined by Andy Hoskins and Mike Green who will remain as first team coaches.
Director Alex Petheram told the club’s website: “I’m delighted to announce that Cookie has been given PFA approval to manage Gloucester City with Hosky and Greener staying on.
“We’re looking to build on the season just gone and develop the club both on and off the field. ”