This study examines the trade of black slaves brought from western Sudan to Morocco during the nineteenth century using statistics from earlier sources and studies. It presents the problems prevalent in using a quantitative approach to the slave trade and the systematic questions it poses. The paper also documents sales techniques and the internal structure of slave markets in Moroccan cities as an institution, reflecting the reality and position of slaves in Moroccan culture. The focus here is on the slave trade, as opposed to slavery, as two separate phenomena. Most societies have hosted various forms of slavery, but not all have actively practiced the trade of slaves, which was banned even as slavery remained prevalent. Thus, the study will explore attitudes opposed to the slave trade in Morocco, including those expressed by Moroccan scholars. The slave trade has gradually receded following the transformations Moroccan society experienced in the first half of the twentieth century.