Based on East Road roundabout, Motorwell is already an established Mitsubishi dealer and aims to draw in more customers with the addition of Fiat.
Directors of the company Adrian Haylett and Graham Elliott have worked on sealing the deal with the Italian carmaker for almost a year and will continue to sell Mitsubishi cars.
The deal will also see Motorwell recruit two new employees as preparations begin for the arrival of the first Fiats in the showroom.
The outlet consists of two onsite showrooms, which dealer principal David Thompson believes helped clinch the deal with the Italian carmaker.
The Motorwell dealership moved to the site in 2012 after the former Southgate Group went into administration.
Thompson told Bridport News: ‘I hope that the choice we can offer will lead more people to the town.
‘It will also allow us to create more career opportunities.
‘It’s good news for Bridport.’