In most OECD countries, consumption absorbs more than three fourths of their country’s GDP. Therefore, the study of their consumption patterns is important. This paper gives up-to-date estimates of income and price elasticities for 9 commodities in each of 37 countries that are members (or affiliates) of the OECD. In addition, the paper presents a detailed analysis of OECD consumption patterns in the form of investigating empirical regularities and testing demand theory hypotheses. Using differential demand equations, we find that the hypothesis of homogeneity hypothesis is supported in all countries; there is some evidence that symmetry is problematic, although we cannot be sure about this; and preference independence (whereby the marginal utility of each good depends only on its consumption) is not rejected in 90% of the countries. The study also finds that income elasticities of rich countries are generally lower than those of poorer countries, and, in general, there is a negative linear relationship between own-price elasticities and income. These elasticities can be used as key inputs in economic policy modelling such as CGE modelling and GST estimation.