Despite globalization, major differences in access and affordability of pharmaceuticals remain across the countries of the world. This dissertation aims at quantifying the differences in the price of pharmaceuticals amongst countries, identifying the factors responsible for these differences, and examining the policy consequences. Paper 1 compares prices in a large set of middle-income countries to some high- and lowincome countries. It finds that prices of pharmaceuticals are inconsistently related to income, with many middle-income countries paying more than some high-income countries and some paying less than countries that are far poorer. Paper 2 confirms the belief that drug prices in United States are generally higher than in 20 other high-income countries, but shows that prices became more similar over the period 1999-2008. Using the values and the range of three price indices (Laspeyres, Paasche, and Fisher) calculated with multilaterally- and bilaterally-matched samples provides a nuanced understanding of these price differences and their evolution. Paper 3 combines price data from middle- and high-income countries to ascertain the social, economic and demographic factors that determine differences in pharmaceutical prices. It finds that prices in middle- and high-income countries are affected differently by competition and globalization and that the greater effect of demographic factors on prices in middle-income countries can give them an inherent disadvantage in early price negotiation. Paper 4 also examines possible determinants of price but in this case focusses on health system characteristics in OECD countries only. The study finds that whilst the overall health system type does not bear any significant relationship with price, governance structures do have a moderately strong relationship with the price and availability of pharmaceuticals. Based on these results, the Conclusion discusses the issue of horizontal and vertical equity in pricing across countries and highlights important policy themes emerging from this work overall.