This paper provides a comprehensive analysis of online price dispersion in Europe, across a broad range of product categories and countries. Using the dominant European price comparison site we collected firm specific prices, weekly, from sevcn European countries (Denmark, France, Italy, Netherlands, Spain, Sweden and the United Kingdom) for 31 unique products, falling into five distinct product categories (printers, PDAs, scanners, games consoles, computer games and music), over the nine month period October 2001 to June 2002. The resulting data set comprises over 17,000 individual price observations. Using a number of alternative measures of price dispersion we find significant differences in the degree of price dispersion observed in online markets, both between countries and across product categories. We consider alternative explanations for online price dispersion and analyse their significance in explaining the observed differences.