Rents generated by natural resources are usually thought to weaken the quality of institutions, particularly in developing countries. Our hypothesis is that this effect may differ depending on the types of natural resources characterized by their different degree of appropriability. We test this hypothesis using panel data covering 90 developing countriesfor the period 1970-2010. We find that total rents weaken the quality of institutions. However, while oil rents have a significant negative effect, forest and mineral rents do not, after controlling for the other relevant determinants of institutional quality, institutional persistence, neighbor effect, and endogeneity of rents.