Seed aid is increasingly applied as an emergency response throughout Africa. This article describes its rise, its goals and the seed security principles which should shape it. Drawing on evidence of the effects of disaster, the article reviews the appropriateness of current seed aid responses and suggests ways to link the type of seed security problem with the type of response employed. Direct seed distribution, the dominant form, seems suited for a subset of conditions when farmers procure seed through formal channels and when seed is not sufficiently available in an area. Seed vouchers and fairs may be more widely applicable as this approach strengthens channels that farmers normally use (both formal and informal) and addresses the more common problem of farmers' lack of access to seed. Key for improving seed aid is a better understanding of how local seed markets function, as these provide a core of seed security in normal and stress periods.