If a slave survived capture in Africa and the long and dangerous "middle passage" across the Atlantic in the hold of a slave ship, he or she could expect further disruption and confusion in the New World. One of the first methods to separate slaves and keep them from uniting against their white masters was to separate Africans from the same region of origin, for the express purpose of eradicating "their own barbarous dialects, customs, and superstitions". This process was less effective in certain areas, such as Brazil, where the Yoruba language survived. Olaudah Equiano, an ex-slave and abolitionist writer in England, gave an eye-witness account of another method of dividing and separating slaves which continued throughout the slaves' lives.

"And at or after a sale it was not uncommon to see negroes taken from the wives, wives taken from their husbands, and children from their parents, and sent off to other islands, and wherever else their merciless lords choose; and probably never more during life to see each other."

There also existed a complex hierarchy of colour pigmentation that served to separate and rank the inhabitants of the New World colonies. The Spanish, for example, had an intricate set of terms for children of parents of different races. A child born of one black and one white parent was referred to as a mulatto, while the child of a mulatto and a white was called a quadroon. A mestizo, or the child of a quadroon and a European was, in the era of the slave trade, considered white and treated to all the resultant privileges. The hierarchy became so complex that the term casta was used to describe anyone not immediately identifiable as either African or European. Such complex social stratification caused division even in family circles, where children of lighter skin tone were more preferable than those who were darker. All of these methods, along with ubiquitous violence or the threat of violence, served to isolate and de-culturise African slaves and make them less prone to unite and revolt against their white masters.

Africans were forced from their homeland and taken across the Atlantic for one purpose: a lifetime of work. African workers were often central to the development and success of New World enterprises and economies. In the early years of colonisation slaves, alongside white labourers, were used primarily in cutting, burning, and clearing bush in order to make the land cultivable and habitable. With the transformation of the land from small farms to large plantations (particularly after the sugar revolution of the 1640s), which vastly increased the number of slaves in the colonies, African labour came to be more heavily relied on, and intense or menial labour of this kind came to be viewed as fit only for African slaves. The kind of work performed by a slave was quite varied, and was based on the age and strength of the slave and the labour being performed. Rural slave labour depended as well on the crop being cultivated and the season. In areas where the indigenous populations had not been completely desecrated, it was they who occupied the lowest social position, and performed the most menial tasks, with the African labour being reserved for more skilled occupations. In areas where the native Americans had been almost completely destroyed, however, Africans were used in any capacity, although the conditions of slave labour always varied depending on the intensity of local economic activity.

The area in which slaves were most vital to burgeoning New World economies was that of sugar production, which was also the most physically exacting crop to farm. The most onerous tasks, performed by the strongest and healthiest individuals, included planting, cutting, and crushing sugar cane. As sugar production became more complex, more skilled slave labour was required. Boilermen, blacksmiths, coopers, masons, and carpenters could all be found on a sugar plantation. The very young, very old, or the infirm were given lighter tasks, such as watching over animals. As well, domestic staff was required for the plantation owner's house, both to work and to act as proof of the owner's wealth and standing. The hierarchy of plantation labour tended to divide the slaves and prevent uprisings, although resistance was always a lurking threat.

Slaves were also vital in the expansion of the production of other labour-intensive crops, including coffee, cacao, tobacco, rice, and, with the invention of Eli Whitney's 'cotton gin', cotton. In Brazil, slaves were also important in the gold mining boom in Mina Gerais, and they were also used as stockmen and cowboys in cattle-breeding areas. Although slavery is primarily associated with rural and agricultural work, slaves could be found in a huge variety of occupations, and urban slavery was an incredibly varied phenomenon. As local economies in the New World became more diverse, so too did the nature of slavery. Slaves were boxers, musicians, teachers, artisans, clerks, entertainers, and performed a wide variety of tasks associated with the shipping industry, including working as sailors. Slaves who could be trusted were often responsible for transporting goods or performing tasks on the wharf, jobs that made it easier for a slave to run away, and many did take advantage of the opportunity. Women could be found in almost every slave occupation except that of the skilled artisan, which was generally passed from father to son. Certain occupations, however, were the almost exclusive domain of women, including work as cooks, domestics, hospital workers, or child-minders. Although working in the house of the planter would increase a slave's status and provide some protection from the hardships of life in the field, there were drawbacks to such a life. One ex-slave, Mary Prince, described her daily occupations as follows:

"She [Mary’s mistress] taught me to do all sorts of household work; to wash and bake, pick cotton and wool, and wash floors, and cook. After Hetty died [...] I had now to milk eleven cows every morning before sunrise, sitting among the damp weeds; to take care of the cattle as well as the children; and to do the work of the house. There was no end to my toils -- no end to my blows."

Although the labour women had to perform was arduous, they sometimes also had to undergo the degradation of becoming a concubine or common-law wife to a planter or other white master. As well, any children born to slave parents were immediately considered slaves themselves, who could be sold as property by the master in spite of the wishes of the parents.