Prior to the 16th century, the bulk of slaves exported from Africa were shipped from East Africa to the Arabian peninsula. Zanzibar became a leading port on this trade.
Arab slave traders differed from European traders in that they would often conduct raiding expeditions themselves, sometimes penetrating deep into the continent. They also differed in that their market greatly preferred the purchase of female slaves over male slaves.

The increased presence of European rivals along the East coast led Arab traders to concentrate on the overland slave caravan routes across the Sahara from the Sahel to North Africa. The German explorer Gustav Nachtigal reported seeing slave caravans departing from Kukawa in Bornu bound for Tripoli and Egypt in 1870. The slave trade represented the major source of revenue for the state of Bornu as late as 1898. Further south, the eastern regions of the Central African Republic have never recovered demographically from the impact of nineteenth-century raids from the Sudan and still have a population density of less than 1 person/km.

The Middle Passage, the crossing of the Atlantic to the Americas, endured by slaves laid out in rows in the holds of ships, was only one element of the well-known triangular trade engaged in by Portuguese, Dutch, French and British. Ships having landed slaves in Caribbean ports would take on sugar, indigo, raw cotton, and later coffee, and make for Liverpool, Nantes, Lisbon or Amsterdam.
Ships leaving European ports for West Africa would carry printed cotton textiles, some originally from India, copper utensils and bangles, pewter plates and pots, iron bars more valued than gold, hats, trinkets, gunpowder and firearms and alcohol. Tropical shipworms were eliminated in the cold Atlantic waters, and at each unloading, a profit was made.

The Atlantic slave trade peaked in the late 18th century, when the largest number of slaves were captured on raiding expeditions into the interior of West Africa. These expeditions were typically carried out by coastal African kingdoms through more formal trade agreements with European traders or by slave raiding parties through more informal bounty agreements with European traders (To see Pedro Blanco).
The people captured on these expeditions were shipped by European traders to the colonies of the New World. As a result of the War of Spanish Succession, the United Kingdom obtained the monopoly (asiento de negros) of transporting captive Africans to Spanish America. It is estimated that over the centuries, twelve to twenty million people were shipped as slaves from Africa by European traders, of whom some 15 percent died during the terrible voyage, many during the arduous journey through the Middle Passage. The great majority were shipped to the Americas, but also went to Europe and the south of Africa.

Some historians conclude that the total loss in persons removed, those who died on the arduous march to coastal slave marts and those killed in slave raids, far exceeded the 65–75 million inhabitants remaining in Sub-Saharan Africa at the trade's end.
Others believe that slavers had a vested interest in capturing rather than killing, and in keeping their captives alive; and that this coupled with the disproportionate removal of males and the introduction of new crops from the Americas (cassava, maize) would have limited general population decline to particular regions of western Africa around 1760–1810, and in Mozambique and neighbouring areas half a century later. There has also been speculation that within Africa, females were most often captured as brides, with their male protectors being a "bycatch" who would have been killed if there had not been an export market for them.

Modern Africa
Slavery persists in Africa more than in all other continents. Slavery in Mauritania was legally abolished by laws passed in 1905, 1961, and 1981, but several human rights organizations are reporting that the practice continues there.
The trading of children has been reported in modern Nigeria and Benin.
In parts of Ghana, a family may be punished for an offense by having to turn over a virgin female to serve as a sex slave within the offended family. In this instance, the woman does not gain the title of "wife".
In parts of Ghana, Togo, and Benin, shrine slavery persists, despite being illegal in Ghana since 1998. In this system of slavery, sometimes called trokosi (in Ghana) or voodoosi in Togo and Benin, or ritual servitude, young virgin girls are given as slaves in traditional shrines and are used sexually by the priests in addition to providing free labor for the shrine.
In the Sudan, slavery continues as part of an ongoing civil war. Evidence emerged in the late 1990s of systematic slavery in cacao plantations in West Africa.