Relying mainly on the manuscript records of the Royal African Company, we explore the factors that contributed to the large gap between slave prices in Africa and the Caribbean. Twenty-two voyages from the mid-1680s are analyzed. These were conducted with hired ships and the payments to the shipowners and captains were recorded. In addition to transport costs, mortality and morbidity had a big effect on slave prices; while the earnings from the trade in gold and ivory had a moderating influence. The effect of mortality and transport costs on slave prices during the eighteenth century is also explored. [ABSTRACT FROM AUTHOR].