Furious Birmingham Pride organisers are concerned they could be "forced out" of the city centre and away from the Gay Village to make way for proposed new offices and flats.
Smithfield has housed Birmingham Pride, the city's largest festival, three times - with a fourth event planned for May 2023.
The 17-hectare site was formerly home to Birmingham's Wholesale Markets and hosted the beach volleyball and 3x3 basketball competitions during the Commonwealth Games, last summer.
Under new proposals, 82,000 sqm of office space, 3,079 new apartments and 44,000 sqm of retail will be built on the site by 2035 - with work taking up to 10 years.
Lendlease said its planned development will “provide the community with a new public square with space for public art activities", but Pride organisers said the plans will not be able to accommodate the 20,000 people who attend the festival every year.
Lawrence Barton, director of Birmingham Pride, tells ITV Central "Pride belongs in the city"
Lawrence Barton said the proposal falls "well short" of what they were promised, leaving them with a space which can only hold less than a quarter of their footfall.
Gay Village is seen as a safe and accepting space by members of the LGBTQ+ community and now they feel like they're being "forced out" of their home.
Mr Barton continued: “The only city-centre site that can accommodate Pride at the size it is now, is Smithfield. This development will force us out of the city centre.
“Moving it away from the gay village, for example to Cannon Hill Park, would also withdraw all the benefits LGBTQ+ venues get from the festival which brings thousands of visitors.”
Birmingham City Council leader Councillor Ian Ward said they will make sure Pride has a "future" in Birmingham.
"I'm absolutely committed to ensuring that Birmingham Pride has a long-term future in this city and I'm continually in talks with the organisers," he said.
"Together we will make sure that Pride has a future here in Birmingham.
"Birmingham Pride is now the largest community festival held in this city.
"It's an event that I regularly attend and enjoy and I've seen it grow from strength to strength.
"It has now grown to such a scale that it is difficult to accommodate it, but we will find a permanent solution to the challenges that Pride faces."
Pride organisers and activists within the LGBTQ+ community said Pride events are essential opportunities to celebrate minority groups.
In 2021, the city council laid temporary tarmac along New Street where new tram lines were being installed, so the annual pride parade could take place along its usual route.
But organisers fear the will to keep Birmingham Pride's home in the city centre, appears to be lacking.
Southside is also the home to the majority of the city’s gay venues, which benefit financially from hosting Pride on their doorsteps.
ITV News Central has approached Lendlease for a comment.