It has long been generally supposed that the kingdom of Kongo suffered a severe decline in population due to the civil wars of the seventeenth century and the slave trade. These figures are derived from literary estimates made by travellers and missionaries of the time. New estimates of population can be obtained by combining the statistics of baptisms left by the missionaries who lived in Kongo with a reconstruction of the age structure of the kingdom. Use of these estimates permits more exact calculations for the period 1650-1700, which suggest a much lower population level-about 500,000-than the commonly accepted figure of two million. This discovery suggests that the postulated population disaster did not occur; instead, it seems that levels of population remained relatively stable, growing slightly throughout the period in question. In addition to revising estimates of population, it has been possible to use the available statistics to throw light on the age structure and vital rates that prevailed in Kongo in the late seventeenth century, as well as to examine certain factors that have impinged on population.