This paper examines the effects of the transatlantic slave trade on political instability in precolonial Africa. I exploit variation on locations of European slave ports, and combine it with time variation arising from the Americas’ sudden increased demand for African slaves in 1680. Using data on ruler duration on over 2,500 precolonial African rulers in the period between 1200 and 1900, I show that African rulers after 1680 had shorter lengths of ruler tenure if they were situated in the vicinity of slave ports. These findings are supported by IV-estimation that uses the distance from slave destinations in the Americas to instrument for proximity to slave ports in Africa.