In 1972, the governments of the PDRY and the YAR declared that they approved a future union. little progress was made toward unification, and relations were often strained. In 1979, simmering tensions led to fighting, which was only resolved after Arab League mediation. The goal of unity was reaffirmed by the northern and southern heads of state during a summit meeting in Kuwait in March 1979. that same year the PDRY began sponsoring an insurgency against the YAR. In April 1980, PDRY President Abdul Fattah Ismail resigned and went into exile. His successor, Ali Nasir Muhammad, took a less interventionist stance toward both the YAR and neighboring Oman. On January 13, 1986, a violent fight began in Aden between Ali Nasir Muhammad and the returned Abdul Fattah Ismail and their supporters. Fighting lasted for more than a month and resulted in thousands of casualties, Ali Nasir's ouster, and Ismail's death. Some 60,000 persons, including Ali Nasir and his supporters, fled to the YAR.

In November 1989, the leaders of the YAR (Ali Abdallah Saleh) and the PDRY (Ali Salim Al-Bidh) agreed on a draft unity constitution originally drawn up in 1981. The Republic of Yemen (ROY) was declared on May 22, 1990. Ali Abdallah Saleh became President, and Ali Salim Al-Bidh became Vice President.

In 1994, amendments to the unity constitution eliminated the presidential council. President Ali Abdallah Saleh was elected by Parliament on October 1, 1994 to a 5-year term. The constitution provides that henceforth the President will be elected by popular vote from at least two candidates selected by the legislature. Yemen held its first direct presidential elections in September 1999, electing President Ali Abdallah Saleh to a 5-year term in what were generally considered free and fair elections. Yemen held its second multiparty parliamentary elections in April 1997. In April 2003, the third multiparty parliamentary elections were held with improvements in voter registration for both men and women and in a generally free and fair atmosphere. Two women were elected. Constitutional amendments adopted in the summer of 2000 extended the presidential term by 2 years, thus moving the next presidential elections to 2006. The amendments also extended the parliamentary term of office to a 6-year term, thus moving elections for these seats to 2003. On February 20, 2001, a new constitutional amendment created a bicameral legislature consisting of a Shura Council (111 seats; members appointed by the president) and a House of Representatives (301 seats; members elected by popular vote).