OBJECTIVES: Many countries employ an external reference pricing system where the price of pharmaceutical is in part governed by the price in selected other countries thus creating a web of relationships between the prices in different countries. The objective of this study was to investigate which countries could be considered the most influential in this network. METHODS: The price referencing pattern between countries in the European Economic Area was represented as a directed graph with each individual country as a node and the existence of price referencing from one country to another as a directed edge. The importance of each country was estimated by calculating the eigenvector centrality of each node based on the adjacency matrix representing the edges of the graph. In an extension, we also performed an analysis where edges were weighted by the size of the pharmaceutical market in each country. RESULTS: When considering unweighted referencing between countries, Germany and France were the two most influential countries followed by Italy, Spain and Hungary ahead of a group of six countries of about equal impact. When weighing edges between countries by market size the picture changed somewhat with Germany still the most important country ahead of Italy, UK, France and Spain. CONCLUSIONS: Taking the entire web of price referencing relationships into consideration provides somewhat different conclusions than just counting the number of countries referencing a single country when assessing the importance of that particular country. Likewise, when incorporating the market size of each country, this gives a different result than just ranking countries by market size alone.