A organisation that represented around 2,000 GPs has reached agreement with the Unite union to be represented by them.
Earlier this year, the National Association of GPs encountered financial difficulties and other controversies which led to it being wound down.
It has now completed negotiations with the Unite union, which will advocate on its behalf.
Unite will provide rules, structures, office space, licencing and campaign support to lobby government, the HSE and others.
Unite Senior Officer Brendan Ogle said that Unite in the Republic currently has no experience in representing family doctors at a formal level.
A General Practice Branch will be established to provide this through Unite.
Mr Ogle said that Unite is Ireland's second largest general trade union, is affiliated to the Irish Congress of Trade Unions and holds a trade union negotiating licence.
Unite said that a powerful voice for General Practice is needed for an improved health service.
The NAGP was originally formed as the Alliance of Family Doctors in 1999.