What factors determined the timing and duration of West European colonization? These colonization decisions have had profound economic, institutional, and social effects. Colonization is the process of creating a new and lasting political organization through invasion, conquest, and/or settlement, with a remote mother country that claims exclusive possession of the colony. The recent empirical literature finds that earlier transition to agriculture, longer statehood experience, and more advanced technology in 1500 AD delayed colonization. Using cross-country data from 136 present-day countries over 1462–1922 AD, we examine a novel hypothesis for which we find robust support: inherent land productivity was a positive determinant of colonization of new areas, and the duration of colonization. In contrast, several factors identified in the literature appear insignificant once we include land productivity. Plausible mechanisms are the need for immediate and continued food self-sufficiency, and the export potential back to a food- and resource-scarce Europe.