World Kidney Day is an appropriate time to reflect on the epidemics(s) of chronic kidney disease (CKD) of undetermined cause (CKDu) that are affecting agricultural communities in Central America, South Asia, and possibly other parts of the world.1, 2, 3, 4 The cause(s) of CKDu remain to be established, with heat, pesticides, water (including heavy metals), infections, or other factors being suggested as the primary cause(s). However, we still do not know, at least on a global level, who gets this disease, or even if the disease is the same in different parts of the world. This lack of basic epidemiological information also has important implications for health care. World Kidney Day 2019 has a theme of “health care access for all,” but health care access cannot be provided for a disease that is unrecognized, undiagnosed, and (even when diagnosed) often untreated. CKDu is clinically silent in the early stages and, in many of the affected areas, carries a poor prognosis. It is usually diagnosed late, and no data are available on factors predicting progression. Renal replacement therapy is unavailable in many low- and middle-income countries,5 and even if present, it is often inaccessible to most of the population, meaning that end-stage renal disease is usually fatal. In addition to the young lives lost, CKDu has a substantial negative impact on social and economic development of affected countries, through jeopardizing the economic development of the affected communities, and straining the poorly resourced health systems of the affected countries.