Twin children have a higher mortality rate than singletons. This situation is all the more worrying in Sub-Saharan Africa, where mortality is already at higher levels. In this work, we are making a complementary contribution to all existing ones, but by mobilizing other types of data less commonly used to analyse twin over-mortality: longitudinal data from about 21 HDSSs. It compares survival curves between twins and singletons over the period 2010-2014 and it presents the evolution over time (from 1995 to 2014) of these curves. It also studies the factors associated with the survival differential between under 5 twins and singletons. The results show the existence of significant disparities between HDSSs in terms of the survival differential between twins and singletons. They also show that the survival differential between twins and singletons narrows over time, and that there would be practically no more twin excess deaths after 5th year age.