Roots and tubers are not well documented in Indonesian historiography. Colonial civil servants regarded root crops as famine food, and they were rarely included in indigenous chronicles. This article presents data for the period 1500 to 1950 on the most important indigenous Indonesian roots and tubers--taro and yams. It looks at the geographical spread of these crops and their social and economic importance--dealing also briefly with adjacent areas like the Malay Peninsula and the Philippines. This is followed by the story of the introduction of the New World roots and tubers: sweet potato, bengkuang, (Irish) potato, and cassava. The article analyzes the differences between the various crops as regards their spread in time and space and the reasons that the indigenous roots and tubers were pushed aside by the alien crops. In conclusion, the findings are related to various economic, social, cultural, and political developments and to the rizification hypothesis.