Despite his defeat in the 2005 legislative elections, Santana Lopes retained his seat at the Assembly of the Republic. He would also resume his functions as Mayor of Lisbon, which had been suspended since he took office as Prime Minister. However, he decided not to seek another term on the 2005 local elections, being succeeded by his deputy, Carmona Rodrigues, who had replaced him during his premiership. In October 2007, after the election of Luís Filipe Menezes as leader of the Social Democratic Party, he was invited to lead the PSD Parliamentary Group, a position he held until Menezes' resignation in June 2008.