In the 1960s and 1990s, internal strife in Rwanda has caused a mass flow of refugees into neighbouring countries. This paper explores the cumulated fertility of Rwandan refugee women and the survival of their children. To this end, we use a national survey covering 6420 former refugee and non-refugee households conducted between 1999 and 2001. The findings support old-age security theories of reproductive behaviour: refugee women had higher fertility but their children had lower survival chances. Newborn girls suffered more than boys, suggesting that the usual sex differential in child survival observed in most populations changes under extreme living conditions.