To explain fertility trends in Africa and the possible obstacles to fertility decline, it is not sufficient simply to examine change in behaviour and the barriers to change among women. In societies where inequalities between men and women are numerous, it is important to find objective indicators of social relations between spouses. In this article Magali Barbieriand Véronique Hertrichexamine the relationship between contraceptive practice and age difference between spouses. Despite a general downward trend, sub-Saharan Africa is still the continent where mean age differences between spouses are the largest. Comparing eighteen countries, the authors show that, after controlling for level of education, modern contraception is most widely used by couples with the smallest age difference. Conversely, women married to much older men always have a lower level of contraceptive use, and this illustrates their disadvantage in terms of individual decision-making power and in the elaboration of shared conjugal projects