The Union of Sardinians – Nationalist Project (Unione dei Sardi – Progetto Nazionalitario, UdS–PN), previously known as Sardinian Democratic Union (Unione Democratica Sarda, UDS) was a regionalist,^[1] Sardinian nationalist and Christian-democratic^[1] political party in Sardinia.

The Sardinian Democratic Union was founded in 1998 as Sardinian section of Democratic Union for the Republic of Francesco Cossiga, a Sardinian who had been Prime Minister and President of Italy. In the 1999 regional election Floris won 6.2% as candidate for president, while the party won 4.1% and three regional councillors. Subsequently, UDS leader Mario Floris, a former Christian Democrat, was President of the Region from 1999 to 2001.

In the 2004 regional election the UDS, which had been re-established taking the current name,^[2] won 3.9% of the vote and two regional councillors. After that, the party became a stable regional ally of The People of Freedom (PdL). In the 2009 regional election, in coalition with the centre-right, the UDS won 3.5% of the vote and got two regional councillors elected (Floris and a member of the New Italian Socialist Party). In the 2010 provincial elections the party was strongest in the Province of Cagliari, where it won 3.8% of the vote.^[3]

Since 2008 the party was for a while the regional section of the Alliance of the Centre, a small party that was later merged into PdL.^[4]

In the 2014 regional election the UdS–PN obtained 2.6% of the vote and Floris was once again re-elected to the Council.^[5]

In the 2019 regional election the UdS–PN obtained 1.1% of the vote and no seats in the Regional Council.

• Secretary: Mario Floris (1998–2018), Antonio Nicolini (2018–present)