In early 1994, Kagera - a region in northwestern Tanzania - was flooded by more than 500,000 refugees fleeing from the genocides of Burundi and Rwanda. I use this population shock and a series of topographic barriers that resulted in variation in refugee intensity to investigate the short- and long-run causal effects of hosting refugees on outcomes of local children. This strategy provides evidence of adverse impacts over one year after the shock: a worsening of children's anthropometrics (0.3 standard deviations), an increase in the incidence of infectious diseases (15-20 percentage points) and an increase in mortality for children under five (7 percentage points). I also find that intra- and inter-cohort variation in childhood exposure to the refugee crisis reduced height in early adulthood by 1.8 cm (1.2%), schooling by 0.2 years (7.1%) and literacy by 7 percentage points (8.6%). Designs using the distance to the border with Rwanda as an alternative identification strategy for refugee intensity support the findings. The estimates are robust across different samples, specifications and estimation methods and provide evidence of a previously undocumented indirect effect of civil wars on the well-being of children and subsequent economic growth in refugee-hosting communities.