Coventry City Council is calling on the government to change its mind over its decision to allow just one Las Vegas- style super casino in the UK.
A number of cities, including Coventry, are competing against each for the right to host the casino.
The city council along with 19 other local authorities wants the government to go back to its original plan to allow eight to be built.
They signed a joint statement to have the number of casino licenses restored.
Coventry is currently competing with Birmingham, Blackpool and Glasgow among others for the sole right to have a super casino.
Such competition could limit the city's hopes of building a casino as part of the Ricoh Arena Complex which would create up to 5,000 jobs.
John McGuigan, Director of City Development for Coventry, said the letter places further pressure on the government to rethink its decision.