What is the relation between the cognitive competence of a national population that nation's economic prosperity? Lynn and Vanhanen [Lynn, R. & Vanhanen, T. (2002). "IQ and the wealth of nations." Westport, CT: Praeger.] presented data pointing to an exceptionally strong relationship between IQ scores and Gross Domestic Product per capita (GDP/c). However weaknesses in the Lynn and Vanhanen data set greatly reduce its construct validity. We re-examine the Lynn and Vanhanen data set and find that although the correlation between the IQ scores and GDP/c is approximately the same in developed and developing nations the absolute error in prediction of GDP/c from IQ is greater in the developing than the developed nations. We then show that recently obtained contemporary educational data from the Program for International Student Assessment (PISA) provides a better predictor of national wealth than does the Lynn-Vanhanen data set. We conclude that in spite of the weaknesses several of their data points Lynn and Vanhanen's empirical conclusion was correct, but we question the simple explanation that national intelligence causes national wealth. We argue that the relationship is more complex.