This study specifies and estimates a gravity model for interprovincial migration in Indonesia. Analysing five cross-sections for Indonesia's 26 provinces for five survey years between 1930 and 2000 we show that throughout the twentieth century economic factors were more important in the explanation of interprovincial migration patterns in Indonesia than planned migration policy aimed at the redistribution of the population. In addition, our regression analysis demonstrates that the urban primacy of Jakarta, Indonesia's capital, had a strong effect on the direction and size of migration flows. Our findings thus suggest that the costly government-supported migration is not very successful and that a strongly centralized government induces migration flows to the capital. These findings have policy implications for other developing countries.