(en) Under colonial rule, the Congo has been a particular focus on the demographic. The colonial literature on this subject is abundant and the statistics are quite numerous (administrative censuses, demographic surveys). However, whole sections of the Congolese population remain unexplored. This applies to the study of mortality under colonial rule. The main reason for this shortcoming is the lack of reliable statistics. The aim of this thesis is to present a method to exploit the available data and show results in terms of mortality and in terms of evolution of the Congolese population. By using the properties of model life tables and tables of stable populations, we can use the data structure (distribution by age and sex) of the population to rebuild life tables. It can cover a period from 1937 to 1956. By using backward-projection, we can estimate the evolution of the whole population from 1955 to 1885.