Up to 1,000 delegates are expected to visit the Brighton Dome from 30 September to 2 October, generating an anticipated economic benefit of £1.5 million.
The IAYMH conference will mark the official launch of the organisation, which was formed in 2010.
The IAYMH is a membership organisation for professionals, researchers, policy makers, young people and families, working in the mental health field.
IAYMH’s PCO, Ronan Flood of advantage Ico, adds: "Brighton has offered a good quality package and its close proximity to London and its major airports and travel links make it an accessible and affordable option.
"The city itself has a great range of restaurants, heritage and attractions and the Dome Complex offers the convenience of three stylish and versatile venues all under one roof."