A country is considered to be dependent on commodity exports when commodities constitute the predominant share of its exports. The combination of a high concentration of exports and the large share of commodities in those exports has important implications for development. In particular, export concentration on primary commodities, or “commodity dependence”, has long been conceptually and empirically linked with underdevelopment. Despite the importance of measuring and analysing commodity dependence, there have been few efforts to empirically analyse and monitor its different dimensions, apart from some national or regional studies. This study seeks to fill this gap by contributing to a better monitoring of world commodity dependence and improving an understanding of the challenges it poses to development. 1. Introduction -- 2. Commodity dependence around the world -- 3. An empirical exploration of the link between income level, export concentration and commodity dependence -- 4. The evolution of world commodity dependence, 1998–2017, and the commodity price cycle -- 5. Did CDDCs diversify their exports and productive sectors between 1998 and 2017? -- 6. Commodity price bust, GDP growth and external debt in CDDCs -- 7. Conclusions and brief policy discussion -- Annex 1. The 50 most commodity-dependent countries -- Annex 2. Countries covered by the data used in section 3.