The Isle of Bioko, formerly Fernando Poo, was discovered by the Portuguese man Fernando Poo in 1472, who gave it the name of Formosa that would soon be transformed into that of its discoverer. The rights of Spain came into existence three centuries later, as a result of the El Pardo treaty, signed in 1778, confirming the preliminary agreement of San Ildefonso of the previous year. These titles gave Spain the possession of the isles of Fernando Poo and Annobón, as well as the right to trade freely along the coast, from Cape Formosa, in the mouth of the Niger River, to Cape López, at the south of the Gabon River.

The English settled in 1827 in Fernando Poo and proposed the purchase of the island, an offer that the Spanish government rejected by sending the Llerena expedition, which in 1843 flew the Spanish flag in Santa Isabel, the current Malabo. Later on, in 1900, after a lawsuit concerning the rights acquired by Spain, which were overruled against the latter, it lost its overseas empire and the thousands of kilometres invoked in the Treaty of Paris. Finally Spain only maintained 26.000 square kilometres of the 200.000 square kilometres which formerly corresponded to the Continental Guinea and the 2.000 square kilometres of the islands.

Until 1956, the isles of Fernando Poo and Annobón were part of the territory of Guinea. On the 21st of August 1956 the said territories were organised in provinces under the name of Provinces of the Gulf of Guinea. In compliance to the Law of the 30th of July 1959, they finally adopt the name of Equatorial Spanish Region and were organised in two provinces: Fernando Poo and River Muni. On the 15th of December 1963 the Spanish government held a referendum amongst the population of the two provinces, a project concerning the bases of autonomy which was approved by an overwhelming majority. These territories were thus provided with autonomy officially adopting the name of Equatorial Guinea with common bodies for the whole territory (General Assembly, Governing Council and Commissioner General) and institutions for each province. In November 1965, the 4th Committee of the General Assembly of the United Nations passed a draft resolution in which it asked Spain to establish as soon as possible the date for the independence of Equatorial Guinea. In December of 1966, in the Council of Ministers, the Spanish government agreed to prepare the Constitutional Conference. In October 1967 the said conference, chaired by Fernando María Castiella, the Spanish minister of Foreign Affairs, was inaugurated; leading the Guinean delegation was Federico Ngomo. Once the second stage of the Constitutional Conference ended (17th of April- 22nd of June1968), the conclusions were held to referendum and approved by a 63,1 per cent of the voters. On the 22nd of September the first presidential elections were held and none of the four candidates obtained absolute majority. A week later Francisco Macías Nguema was elected first president of Equatorial Guinea; his immediate follower in the elections was Bonifacio Ondo Edu. On the 12th of October1968 independence was proclaimed under the name of Republic of Equatorial Guinea. It was admitted in the United Nations as the 126th member of the organisation. Due to the increase of insecurity, on the 27th of February 1969 the state of emergency was proclaimed for a fortnight. 

During the night of the 4th to the 5th of March of 1969, armed groups attempted the assault of the residence of the president Macías; apparently they were sent by Bonifacio Ondo and others. In the attack they were wounded and made prisoners; shortly after, their death in the prison of Bata was notified. The unrest created by this event accelerated the exit of the white population from the country.

In July of 1972, Francisco Macías Nguema was proclaimed president for life.

In September troops from Gabon entered the territory of Equatorial Guinea, generating a conflict between both countries. On several occasions they tried to reach an agreement, but the permanent infractions of the agreement by Gabon made relationships very difficult between the two countries. On the 13th of November, in a meeting held in the People’s Republic of Congo, attended by the presidents of Guinea and Gabon, and those of Zaire and Congo, together with the Secretary General of the O.A.U., an agreement was finally reached between the litigant countries.

On the 19th of July 1973 a new Constitution was approved by referendum and subsequently adopted. According to this Constitution, the Guinean Peseta was renamed the Ekwele, the currency which came into force on the 29th of September 1975. 

In March 1975 a new technical cooperation agreement between Spain and Equatorial Guinea was implemented and remained in force until March 1977, when it was cancelled after a speech of the president Macías against the Spanish Crown.