We present a new dataset with 15 indicators for the political, economic and social impact of colonialism. This dataset and our four indices for the impact of colonialism create for the first time the opportunity to compare directly the levels of colonial transformation for a sample of 83 African and Asian countries. Some of our exploratory findings on the interrelation of the dimensions show that in British colonies political domination was in general less direct and less violent. Plantation colonies experienced more investment in infrastructure and more violence during decolonization. The correlations between indicators for economic distortion (trade policy, trade and FDI concentration) show that the economic re-direction of some colonies towards a more exclusive exchange with the metropole country was an interdependent process. In general, a more intense political domination came along with a higher level of economic transformation. If an area was transformed economically, however, a social transformation was likely to take place too, but these processes should not be confounded. In areas that were politically united for the first time under colonialism, economic distortion and social transformation were more profound.