Heather Maxwell, mother of a former resident, said the event helped celebrate the advent of deinstitutionalisation, which had been hugely positive for the intellectually disabled.
More than 160 people with intellectual disabilities entered the community when Cherry Farm closed on November 7, 1992.
The event celebrates five services established in Dunedin to cater for those with intellectual disabilities when Cherry Farm closed.
These include residential projects such as the Hawksbury Community Living Trust, and day centres including the Connections Centre, Corstorphine.
Connections Centre programme manager, Kay Murray, said deinstitutionalisation had been very successful for the intellectually disabled. Instead of being "locked away", they were part of Dunedin, enhancing the community.
In Cherry Farm, they were housed in dormitories of up to 60 residents, she said.
Up to 180 people were attending the ball, including former residents, families and former staff.