Objectives: To construct a number of pharmaceutical price indices for a broad set of countries, covering a range of regions, including countries with different levels of economic development and a representative sample of medicines. Methods: The indices were developed using the Fisher EKS method. In order to construct an index the products needed to be defined as like. The definition of like in this study was based on molecules which are deemed to deliver equivalent health outcomes. This is a very broad definition and allows a large number of countries and molecules to be included in the indices. Two price indices have been constructed. The first compares prices of mostly off-patent medicines across 56 countries over the period from 2005 to 2011 and included 42 molecules which were sold in each country for the period. The second examined on-patent medicines across 17 countries and 9 molecules. Results: The results showed prices varied significantly between regions and that prices of genericised medicines both fell and converged over time. For the mostly generic drugs index the regions from lowest to highest price were - Region of the Americas A; South-East Asian Region D; South-East Asian Region B; European Region B; Western Pacific Region A; European Region A; African Region E; European Region C; Western Pacific Region B; Eastern Mediterranean Region D; Region of the Americas D; Region of the Americas B and Eastern Mediterranean Region B. Prices tended to be similar within each region. These results will be presented in detail. Conclusions: This research makes a unique contribution to our understanding of drug prices. It is the largest international comparison of pharmaceutical prices ever undertaken; employs new method to pharmaceutical pricing indices through the Fisher EKS method and outcomes based definitions of equivalence and examines genericised and on-patent markets separately.