Popescu-Tariceanu returned to parliament in 1996, when he was elected as a deputy representing the Democratic Convention of Romania -- an umbrella alliance of rightist political formations, the Hungarian Democratic Federation of Romania (UDMR), and civil-society organizations. Soon after, Popescu-Tariceanu became a minister of state (deputy prime minister) in the cabinet headed by former Prime Minister Victor Ciorbea, in which he also held the portfolio of industry and trade minister between 1996-97. In this position, he set out to dismantle unprofitable mines, which earned him the enmity of miners' trade unions.
Following the formation of the Justice and Truth alliance of the PNL and the Democratic Party in 2003, in March 2004 Popescu-Tariceanu was made manager of the alliance's election campaign for the local elections in June. He was elected a deputy on the PNL-Democratic Party list in the 28 November election. After the withdrawal from the presidential race of PNL-Democratic Party candidate Theodor Stolojan on 2 October, Popescu-Tariceanu was elected to replace Stolojan as co-chairman of the Justice and Truth alliance and designated as the alliance's candidate for prime minister. Bucharest Mayor and alliance co-Chairman Traian Basescu replaced Stolojan as the alliance's presidential candidate and won the 12 December runoff against former Prime Minister Adrian Nastase.