OBJECTIVES: International pharmacoeconomic studies should comply with methodological guidelines, which state that cost data must be country-specific and clearly referenced. This study aims to identify the different requirements in each country and report costing sources that can be used. It also establishes common requirements between countries, and identification and data type issues in each country. METHOD: Seven European countries were chosen for analysis. Literature was analysed to review current pharmacoeconomic guidelines, costing requirements and perspective that should be adopted. Using the review results, and researchers with pharmacoeconomic expertise and local country knowledge, relevant country costing sources were found. Each source was reviewed and data extracted into an international costing sources database. Particular attention was given to the reliability of the source, price year, frequency of updates, type and level of costing, allowing meaningful comparisons between countries. RESULTS: Even though an important issue in international economic studies is cross-country cost analyses, there was very little published literature showing combined synthesis of costing sources. International guidelines tended to recommend the use of direct costs, particularly from the perspective of the government or third party payer. Main internationally recognised medical direct costs include medical visits, pharmaceuticals and hospitalisations, but between countries, the costing units may differ. The level of costing varied among countries and several reported hospitalisations costs are at DRG (Diagnosis Related Group) or specialty levels, for example. The frequency of price updates was not similar among countries, generally from one to three years. CONCLUSION: The database was populated following pharmacoeconomic guidelines, ensuring relevance, accuracy and quality of cost data collection. These factors are essential in conducting economic evaluations. This summarising of data allows an easy way of identifying what is available in each country and what methods should be adopted when performing pharmacoeconomic cost analyses. With research sponsors often looking towards international economic models and analyses, such timely information is important.