Cornwall Council has voted to approve the partial funding of a new stadium in the county.
Councillors have decided to provide £3m towards the total estimated budget of £14.3m.
Cornish Pirates rugby team, Truro City football club and Truro and Penwith College have put up £6m of the cash and they are hoping the government will provide another £3m.
Planning permission for the stadium has already been granted.
The Cornwall Council money is coming from the authority's Economic Development Match Funding budget and will not affect local services.
Councillors voted 69 in favour of providing funding for the stadium with 41 against and seven abstentions.
Under the council's agreement, the funding will only be provided should the government also hand over £3m.
It is also dependent on a full business plan for the scheme being approved by the authority's chief finance officer and it will be assessed by an independent expert.
Conservative MP for St Ives Derek Thomas has revealed he is due to meet with Secretary of State Matt Hancock on Wednesday to discuss possible government funding for the stadium.
The team behind the stadium, which is hoping to raise another £2m through private investors and crowdfunding, hopes to have it ready for the beginning of the 2019 rugby season.
Cornish Rebels rugby league team and American Sharks American Football would also use the ground.
The Stadium for Cornwall is planned for a site just off the A390 near Threemilestone on the outskirts of Truro.
The ground would initially have a capacity of 6,000 - with the option to extend to 15,000 - with an artificial pitch.
A health club and Cornwall's "biggest conference facility" would also be attached to the project.
Stadium for Cornwall timeline
- June 2005: Truro City submits an application for a 16,000-seat stadium at Treyew Road
- September 2007: Cornwall Council overturns approval for a cheaper stadium at Kenwyn
- February 2008: Cornish Pirates and Truro City groundshare plans collapse
- May 2010: Cornwall Council launches feasibility study into ground
- May 2012: Councillors vote against public funding
- January 2014: Developers say supermarket would fund stadium
- April 2015: Truro City submit plans for rival ground
- July 2015: PM David Cameron lends support as planning permission given
- December 2016: Pirates director estimates work will start "in middle of 2017"
- March 2017: Truro chairman told their ground is not viable
- April 2017: Truro and Pirates set to share Stadium for Cornwall
- January 2018: Cornish Pirates & Truro City groundshare "needs public funding"